Changes in properties of heavy hadrons with a charm or a bottom quark are studied in nuclear matter. Effective masses (scalar potentials) for the hadrons are calculated using quark–meson coupling ...model. Our results also suggest that the heavy baryons containing a charm or a bottom quark will form charmed or bottom hypernuclei, which was first predicted in mid-70s. In addition a possibility of B−-nuclear bound (atomic) states is briefly discussed.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted) We use methods of quantum field theory in toroidal topologies to study the N-component D-dimensional massive Gross-Neveu model, at ...zero and finite temperature, with compactified spatial coordinates. We discuss the behavior of the large-N coupling constant (g), investigating its dependence on the compactification length (L) and the temperature (T). For all values of the fixed coupling constant (lambda), we find an asymptotic-freedom type of behavior, with g arrow right 0 as L arrow right 0 and/or T arrow right infinity. At T = 0, and for lambda > or = ... (the strong-coupling regime), we show that, starting in the region of asymptotic freedom and increasing L, a divergence of g appears at a finite value of L, signaling the existence of a phase transition with the system getting spatially confined. Such a spatial confinement is destroyed by raising the temperature. The confining length, ..., and the deconfining temperature, ..., are determined as functions of lambda and the mass (m) of the fermions, in the case of D = 2, 3, 4. Taking m as the constituent quark mass (approximate 350 MeV), the results obtained are of the same order of magnitude as the diameter (approximate 1.7 fm) and the estimated deconfining temperature (approximate 200 MeV) of hadrons.
The Seiberg-Witten formalism has been realized as an electrodynamics in phase space (associated to the Dirac equation written in phase space) and this fact is explored here with non-abelian gauge ...group. First, a physically heuristic presentation of the Seiberg-Witten approach is carried out for non-abelian gauge in order to guide the calculation procedures. These results are realized by starting with the Lagrangian density for the free Dirac field in phase space. Then a field strength is derived, where the non-abelian gauge group is the SU(2), corresponding to an isospin (non-abelian) field theory in phase space. An application to nucleon is then discussed.
•In the paper we obtain Lie and non-classical symmetries for the non-linear Dirac equation with a quartic potential for 1+1 and 2+1 dimensions.•We reobtained previous results for Lie Symmetries in ...the 1+1 case.•Non-classical symmetries in 1+1 dimensions coincide with Lie symmetries.•New original results are obtained for both Lie and non-classical symmetries in 2+1.•Such symmetries are used to obtain new original and highly non-trivial invariant solutions of the non-linear Dirac equation of the type considered in the paper.•Some considerations to extend the study are also given.
We apply Lie and non-classical symmetry methods to partial differential equations in order to derive solutions of the non-linear Dirac equation corresponding to the Gross–Neveu model in d=(1+1) and d=(2+1) space–time dimensions. For each d, we first identify sub-algebras of the Poincaré–Lie algebra and for each such sub-algebra, we calculate the invariant solution. Non-classical symmetries are also determined and used to derive new solutions for the Gross–Neveu model.
Ras is one of the most frequently activated oncogenes in cancer. Two mitogen-activated protein kinases (MAPKs) are important for ras transformation: extracellular signal-regulated kinase (ERK) and ...c-Jun N-terminal kinase 2 (JNK2). Here we present a downstream signal amplification cascade that is critical for ras transformation in murine embryonic fibroblasts. This cascade is coordinated by ERK and JNK2 MAPKs, whose Ras-mediated activation leads to the enhanced levels of three oncogenic transcription factors, namely, c-Myc, activating transcription factor 2 (ATF2) and ATF3, all of which are essential for ras transformation. Previous studies show that ERK-mediated serine 62 phosphorylation protects c-Myc from proteasomal degradation. ERK is, however, not alone sufficient to stabilize c-Myc but requires the cooperation of cancerous inhibitor of protein phosphatase 2A (CIP2A), an oncogene that counteracts protein phosphatase 2A-mediated dephosphorylation of c-Myc. Here we show that JNK2 regulates Cip2a transcription via ATF2. ATF2 and c-Myc cooperate to activate the transcription of ATF3. Remarkably, not only ectopic JNK2, but also ectopic ATF2, CIP2A, c-Myc and ATF3 are sufficient to rescue the defective ras transformation of JNK2-deficient cells. Thus, these data identify the key signal converging point of JNK2 and ERK pathways and underline the central role of CIP2A in ras transformation.
We discuss a way to obtain information about higher dimensions from observations by studying a brane-based spherically symmetric solution. The three classic tests of General Relativity are analyzed ...in detail: the perihelion shift of the planet Mercury, the deflection of light by the Sun, and the gravitational redshift of atomic spectral lines. The braneworld version of these tests exhibits an additional parameter
b
related to the fifth-coordinate. This constant
b
can be constrained by comparison with observational data for massive and massless particles.
The early trajectory of skin fibrosis provides insights into the disease course of systemic sclerosis (SSc) including mortality; however, little is known about late skin fibrosis. The aims of our ...study were to ascertain the prevalence and characteristics of late skin fibrosis in SSc.
We developed and tested three conceptual scenarios of late (>5 years after first non-RP feature) skin fibrosis including new worsening of skin disease, and failure to improve after worsening within 5-year window. We defined skin worsening as change in modified Rodnan skin score (mRSS) ≥5 units or ≥25%. Using strict inclusion criteria including complete mRSS, we identified 1,043 (out of 19 115) patients within the EUSTAR database for our analysis. We further restricted analysis within 887 (out of 1043) patients who had lcSSc or dcSSc at baseline.
One-fifth of patients among the whole cohort (n = 208/1043, 19.9%) experienced mRSS worsening, including in patients with lcSSc or dcSSc at baseline (n = 193/887, 21.8%). This was largely due to new skin worsening after the 5-year window or failure to improve with worsening within the 5-year window. Patients with lower baseline mRSS and lcSSc were more likely to develop late skin fibrosis. Anti-Scl-70 was associated with progression from baseline lcSSc to dcSSc, and anticentromere was protective.
Late skin fibrosis is not uncommon in SSc. We have identified different patterns relevant to clinical practice and trial design. Late skin fibrosis is a neglected manifestation of SSc and warrants further investigation including to determine clinical outcomes and optimal therapeutic strategy.
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