357 research outputs found
Three-dimensional phase transitions in multiflavor lattice scalar SO(N_{c}) gauge theories
No full textWe investigate the phase diagram and finite-temperature transitions of three-dimensional scalar SO(N_{c}) gauge theories with N_{f}≥2 scalar flavors. These models are constructed starting from a maximally O(N)-symmetric multicomponent scalar model (N=N_{c}N_{f}), whose symmetry is partially gauged to obtain an SO(N_{c}) gauge theory, with O(N_{f}) or U(N_{f}) global symmetry for N_{c}≥3 or N_{c}=2, respectively. These systems undergo finite-temperature transitions, where the global symmetry is broken. Their nature is discussed using the Landau-Ginzburg-Wilson (LGW) approach, based on a gauge-invariant order parameter, and the continuum scalar SO(N_{c}) gauge theory. The LGW approach predicts that the transition is of first order for N_{f}≥3. For N_{f}=2 the transition is predicted to be continuous: It belongs to the O(3) vector universality class for N_{c}=2 and to the XY universality class for any N_{c}≥3. We perform numerical simulations for N_{c}=3 and N_{f}=2,3. The numerical results are in agreement with the LGW predictions
Constraints on the two-flavor QCD phase diagram from imaginary chemical potential
No full textWe review our knowledge of the phase diagram of QCD as a function of temperature, chemical potential and quark masses. The presence of tricritical lines at imaginary chemical potential m = i p 3 T, with known scaling behaviour in their vicinity, puts constraints on this phase diagram, especially in the case of two light flavors. We show first results in our project to determine the finite-temperature behaviour in the Nf = 2 chiral limit
Regulation of proliferation and cytokine expression of bone marrow fibroblasts: role of c-myb.
No full textThe c-myb protooncogene plays a major role in regulating the process of in vitro and in vivo hematopoiesis via its activity as transcriptional regulator in hematopoietic progenitor cells. Since the bone marrow microenvironment appears to regulate in vivo hematopoiesis by maintaining the growth of multipotent progenitors via secretion of specific cytokines, we asked whether c-myb is also required for the proliferation of and/or cytokine production by stromal cells that generate fibroblast-like colonies (fibroblast colony-forming units [CFU-F]). Using the reverse transcriptase polymerase chain reaction technique, we detected low levels of c-myb mRNA transcripts in human normal bone marrow fibroblasts. Treatment of these cells with c-myb antisense oligodeoxynucleotides caused downregulation of c-myb expression, decreased in the number of marrow CFU-F colonies (approximately 54% inhibition) and in the cell number within residual colonies (approximately 80%), and downregulation of granulocyte/macrophage colony-stimulating factor (GM-CSF) and stem cell factor (SCF) mRNA expression. Transfection of T98G glioblastoma cells, in which expression of c-myb, GM-CSF, and SCF mRNAs is undetectable or barely detectable, with a plasmid containing a full-length c-myb cDNA under the control of the SV40 promoter induced the expression of biologically active SCF and GM-CSF in these cells. Regulation of GM-CSF expression by c-myb was due in part to transactivation of the GM-CSF promoter. These results indicate that, in addition to regulating hematopoietic cell proliferation, c-myb is also required for proliferation of and cytokines synthesis by bone marrow fibroblasts
Agriculture Management and Soil Fauna Monitoring: The Case of Emilia-Romagna Region (Italy)
No full textsoil quality. Here we analyzed soil arthropods community in several agricultural managements (arable land, grassland, vineyard and orchard) located in the Emilia-Romagna region (Italy), whose land was especially exploited for intensive agriculture, in order to state soil health and soil quality, in relation to crop types and management. The computation of the biological soil quality index QBS-ar revealed lower values in arable lands, easily due to management practices applied, in particular ploughing. On the other hand, the QBS-ar values associated to orchards and vineyards were higher: the grassy cover on soil and the reduced farming practices support soil microarthropod communities. Meadows were generally characterized by high index values, related to their age. The application of QBS-ar index as a tool to identify soil quality and, thus, soil functionality, was then confirmed. Starting with this type of approach, further analyses could be crucial to highlight differen
Valutazione dell'attivita proliferativa delle cellule emopoietiche nelle sindromi preleucemiche.
No full textReconfinement, localization, and thermal monopoles in SU (3) trace-deformed Yang-Mills theory
No full textWe study, by means of numerical lattice simulations, the properties of the reconfinement phase transition taking place in trace deformed SU(3) Yang-Mills theory defined on R3×S1, in which center symmetry is recovered even for small compactification radii. We show, by means of a finite size scaling analysis, that the reconfinement phase transition is first order, like the usual SU(3) thermal phase transition. We then investigate two different physical phenomena, which are known to characterize the standard confinement/deconfinement phase transition, namely the condensation of thermal magnetic monopoles and the change in the localization properties of the eigenmodes of the Dirac operator. Regarding the latter, we show that the mobility edge signalling the Anderson-like transition in the Dirac spectrum vanishes as one enters the reconfined phase, as it happens in the standard confined phase. Thermal monopoles, instead, show a peculiar behavior: their density decreases going through reconfinement, at odds with the standard thermal theory; nonetheless, they condense at reconfinement, like at the usual confinement transition. The coincidence of monopole condensation and Dirac mode delocalization, even in a framework different from that of the standard confinement transition, suggests the existence of a strict link between them
Analisi delle unità catalitiche della DNA polimerasi alfa nella leucemia acuta mieloblastica.
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