We compare the mass-radius relationship of strange stars obtained in two theoretical frameworks describing the color-flavor-locking state of dense quark matter: The semi-empirical MIT model and a ...self-consistent approach using the Nambu-Jona-Lasinio (NJL) model. In the simplest MIT model extended to include pairing, one can make the equation of state stiffer by increasing the gap parameter so that larger maximum masses for these objects can be reached. In the NJL model, however, such an effect is not possible. To increase the gap parameter within the NJL model to values comparable to those considered in the MIT case, a noticeably increase of the diquark-coupling-constant strength is needed, but this in turn softens the equation of state producing a lower maximum star mass. This behaviour is interpreted as signalling the system crossover at high diquark coupling from a BCS regime to a BEC one, a process that cannot be reproduced within the simple MIT prescription.
We present the first measurement of the negative pion total hadronic cross section on argon, which we performed at the Liquid Argon In A Testbeam (LArIAT) experiment. All hadronic reaction channels, ...as well as hadronic elastic interactions with scattering angle greater than 5~degrees are included. The pions have a kinetic energies in the range 100-700~MeV and are produced by a beam of charged particles impinging on a solid target at the Fermilab Test Beam Facility. LArIAT employs a 0.24~ton active mass Liquid Argon Time Projection Chamber (LArTPC) to measure the pion hadronic interactions. For this measurement, LArIAT has developed the ``thin slice method", a new technique to measure cross sections with LArTPCs. While generally higher than the prediction, our measurement of the (\(\pi^-\),Ar) total hadronic cross section is in agreement with the prediction of the Geant4 model when considering a model uncertainty of \(\sim\)5.1\%.
We analyze the color-flavor-locked phase of strange quark matter modelled by the three-flavor Nambu-Jona-Lasinio (NJL) framework with and without magnetic field and discuss some additional ...constraints on the stability scenario when a high magnetic field is applied. We compare the results obtained by employing the MIT Bag Model and discuss the pairing gap behavior and its influence on the equation of state.
It is possible that a system composed of up, down and strange quarks consists the true ground state of nuclear matter at high densities and low temperatures. This exotic plasma, called strange quark ...matter (SQM), seems to be even more favorable energetically if quarks are in a superconducting state, the so-called color-flavor locked state. Here are presented calculations made on the basis of the MIT bag model considering the influence of finite temperature on the allowed parameters characterizing the system for stability of bulk SQM (the so-called stability windows) and also for strangelets, small lumps of SQM, both in the color-flavor locking scenario. We compare these results with the unpaired SQM and also briefly discuss some astrophysical implications of them. Also, the issue of strangelet's electric charge is discussed. The effects of dynamical screening, though important for non-paired SQM strangelets, are not relevant when considering pairing among all three flavor and colors of quarks.
Using the solutions of the gap equations of the magnetic-color-flavor-locked (MCFL) phase of paired quark matter in a magnetic field, and taking into consideration the separation between the ...longitudinal and transverse pressures due to the field-induced breaking of the spatial rotational symmetry, the equation of state (EoS) of the MCFL phase is self-consistently determined. This result is then used to investigate the possibility of absolute stability, which turns out to require a field-dependent bag constant to hold. That is, only if the bag constant varies with the magnetic field, there exists a window in the magnetic field vs. bag constant plane for absolute stability of strange matter. Implications for stellar models of magnetized (self-bound) strange stars and hybrid (MCFL core) stars are calculated and discussed.
The exact composition of a specific class of compact stars, historically referred to as "neutron stars", is still quite unknown. Possibilities ranging from hadronic to quark degrees of freedom, ...including self-bound versions of the latter have been proposed. We specifically address the suitability of strange star models (including pairing interactions) in this work, in the light of new measurements available for four compact stars. The analysis shows that these data might be explained by such an exotic equation of state, actually selecting a small window in parameter space, but still new precise measurements and also further theoretical developments are needed to settle the subject.
Strangelets coming from the interstellar medium (ISM) are an interesting target to experiments searching for evidence of this hypothetic state of hadronic matter. We entertain the possibility of a ...{\it trapped} strangelet population, quite analogous to ordinary nuclei and electron belts. For a population of strangelets to be trapped by the geomagnetic field, these incoming particles would have to fulfill certain conditions, namely having magnetic rigidities above the geomagnetic cutoff and below a certain threshold for adiabatic motion to hold. We show in this work that, for fully ionized strangelets, there is a narrow window for stable trapping. An estimate of the stationary population is presented and the dominant loss mechanisms discussed. It is shown that the population would be substantially enhanced with respect to the ISM flux (up to two orders of magnitude) due to quasi-stable trapping.
Trapping of strangelets in the geomagnetic field Paulucci, L.; Horvath, J. E.; Medina-Tanco, G. A.
Physical review. D, Particles, fields, gravitation, and cosmology,
02/2008, Letnik:
77, Številka:
4
Journal Article
An epidemiological study on Q fever in the Emilia-Romagna region, Italy Martini, M. (Univ. Bologna (Italy). Inst. di Malattie Infettive, Profilassi e Polizia Veterinaria); Baldelli, R; Calboli, L.P. de
Zentralblatt für Bakteriologie,
(Jan 1994), 1994-Jan, Letnik:
280, Številka:
3
Journal Article
Bei 711 Rindern aus 99 Bestaenden wurde mittels Komplementbindungsreaktion auf Coxiella burnetii Infektion geprueft. Es ergab sich eine Praevalenzrate von 13,1 % bezogen auf die Bestaende und von 4,4 ...% bezogen auf die Tiere. Die positiven Titer reichten von 1:8 bis 1:256. Die positiven Befunde unterschieden sich signifikant zwischen Tieren unterschiedlichen Alters und unterschiedlicher Rasse sowie zwischen Tieren aus Bestaenden unterschiedlicher Haltung und Produktionsart.
Abstract Background Aberrant accumulation of α-synuclein constitutes inclusion bodies that are considered a characteristic feature of a group of neurological disorders described as synucleinopathies. ...Often, multiple disease-causing proteins overlap within a given disease pathology. An emerging body of research focuses on the oligomeric populations of various pathogenic proteins, considering them as the culprits causing neuronal damage and degeneration. To this end, the use of conformation-specific antibodies has proven to be an effective tool. Previous work from our laboratory and others has shown that oligomeric entities of α-synuclein and tau accumulate in their respective diseases, but their interrelationship at this higher order has yet to be shown in synucleinopathies. Methods Here, we used two novel conformation-specific antibodies, F8H7 and Syn33, which recognize α-synuclein oligomers and were developed in our laboratory. We investigated brain tissue from five of each Parkinson’s disease and dementia with Lewy bodies patients by performing biophysical and biochemical assays using these antibodies, in addition to the previously characterized anti-tau oligomer antibody T22. Results We demonstrate that in addition to the deposition of oligomeric α-synuclein, tau oligomers accumulate in these diseased brains compared with control brains. Moreover, we observed that oligomers of tau and α-synuclein exist in the same aggregates, forming hybrid oligomers in these patients’ brains. Conclusions In addition to the deposition of tau oligomers, our results also provide compelling evidence of co-occurrence of α-synuclein and tau into their most toxic forms, i.e., oligomers suggesting that these species interact and influence each other’s aggregation via an interface in synucleinopathies.
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