Formation of Fluctuations in the Molecular Slab via Isobaric Thermal Instability

The frictional heating by ion-neutral drift is calculated and its effect on isobaric thermal instability is carried out. Ambipolar drift heating of one-dimensional self-gravitating magnetized molecular slab is used under the assumptions of quasi-magnetohydrostatic and local ionization equilibrium. We see that ambipolar drift heating is inversely proportional to density and its value in some regions of the slab can be significantly larger than the average heating rates of cosmic rays and turbulent motions. The results show that the isobaric thermal instability can occur in some regions of the slab; therefore it may produce the slab fragmentation and formation of the AU-scale condensations.Comment: 21 pages, 6 figures, 1 table, accepted by MNRA

Spin-dependent energy distribution of B-hadrons from polarized top decays considering the azimuthal correlation rate

In our previous work, we studied the polar distribution of the scaled energy of bottom-flavored hadrons from polarized top quark decays $t(\uparrow)\rightarrow W^++b(\rightarrow X_b)$, using two different helicity coordinate systems. Basically, the energy distributions are governed by the unpolarized, polar and azimuthal rate functions which are related to the density matrix elements of the decay $t(\uparrow)\rightarrow W^++b$. Here we present, for the first time, the analytical expressions for the ${\cal O}(\alpha_s)$ radiative corrections to the differential azimuthal decay rates of the partonic process $t(\uparrow)\rightarrow b+W^+(+g)$ in two helicity systems, which are needed to study the azimuthal distribution of the energy spectrum of the B-hadron produced in polarized top quark decays. Our predictions of the hadron energy distributions enable us to deepen our knowledge of the hadronization process and to determine the polarization states of top quarks

Heavy quark fragmentation functions at next-to-leading perturbative QCD

It is well-known that the dominant mechanism to produce hadronic bound states with large transverse momentum is fragmentation. This mechanism is described by the fragmentation functions (FFs) which are the universal and process-independent functions. Here, we review the perturbative FFs formalism as an appropriate tool for studying these hadronization processes and detail the extension of this formalism at next-to-leading order (NLO). Using the Suzuki's model, we calculate the perturbative QCD FF for a heavy quark to fragment into a S-wave heavy meson at NLO. As an example, we study the LO and NLO FFs for a charm quark to split into the S-wave $D$-meson and compare our analytic results both with experimental data and well-known phenomenological models

Role of friction in multidefect ordering

We use continuum simulations to study the impact of friction on the ordering of defects in an active nematic. Even in a frictionless system, +1/2 defects tend to align side-by-side and orient antiparallel reflecting their propensity to form, and circulate with, flow vortices. Increasing friction enhances the effectiveness of the defect-defect interactions, and defects form dynamically evolving, large scale, positionally and orientationally-ordered structures which can be explained as a competition between hexagonal packing, preferred by the -1/2 defects, and rectangular packing preferred by the +1/2 defects

Comparison of serum levels of hepcidin and pro-hepcidin in hemodialysis patients and healthy subjects

Hepcidin prevents absorption of iron from the intestine and inhibits release of iron from macrophages and hepatocytes. For this reason, it seems that high levels of hepcidin are a predisposing factor for anemia in chronic inflammatory conditions such as chronic kidney disease and dialysis patients. This study was designed to determine the role of changes in the level of serum hepcidin in the management of hemodialysis patients. This study included 44 dialysis patients and 44 controls. The hepcidin and pro-hepcidin levels were measured by the enzyme linked immunosorbent assay method. The serum ferritin level was measured by the chemiluminescence method. The mean hepcidin level was 999.3 ± 996.7 ng/mL in the case group and 770.4 ± 815.9 ng/mL in the control group (P = 0.25). The mean pro-hepcidin level was, respectively, 186.1 ± 220.3 pg/mL and 150.87 ± 207.7 pg/mL, in the case group and control groups (P = 0.45). The mean (standard deviation) ferritin level was 816.4 ± 379.4 ng/mL in the case group and 193 ± 171.8 ng/mL in the control group (P < 0.001). In the case group, the correlation between serum ferritin and hepcidin was not significant (r = 0.6, P = 0.08). Also, there was no significant correlation between serum ferritin and pro-hepcidin levels (r = 0.6, P = 0.08). A positive correlation was seen between pro-hepcidin and hepcidin levels (r = 0.92, P < 0.01). In this study, the results showed that the serum hepcidin levels are high in dialysis patients and that there was no correlation with the serum ferritin levels