Orthogonal vertical velocity dispersion distributions produced by bars

In barred galaxies, the contours of stellar velocity dispersions ($\sigma$) are generally expected to be oval and aligned with the orientation of bars. However, many double-barred (S2B) galaxies exhibit distinct $\sigma$ peaks on the minor axis of inner bars, which we termed "$\sigma$-humps," while two local $\sigma$ minima are present close to the ends of inner bars, i.e., "$\sigma$-hollows." Analysis of numerical simulations shows that $\sigma_z$-humps or hollows should play an important role in generating the observed $\sigma$-humps+hollows in low-inclination galaxies. In order to systematically investigate the properties of $\sigma_z$ in barred galaxies, we apply the vertical Jeans equation to a group of well-designed three-dimensional bar+disk(+bulge) models. A vertically thin bar can lower $\sigma_z$ along the bar and enhance it perpendicular to the bar, thus generating $\sigma_z$-humps+hollows. Such a result suggests that $\sigma_z$-humps+hollows can be generated by the purely dynamical response of stars in the presence of a, sufficiently massive, vertically thin bar, even without an outer bar. Using self-consistent $N$-body simulations, we verify the existence of vertically thin bars in the nuclear-barred and S2B models which generate prominent $\sigma$-humps+hollows. Thus the ubiquitous presence of $\sigma$-humps+hollows in S2Bs implies that inner bars are vertically thin. The addition of a bulge makes the $\sigma_z$-humps more ambiguous and thus tends to somewhat hide the $\sigma_z$-humps+hollows. We show that $\sigma_z$ may be used as a kinematic diagnostic of stellar components that have different thickness, providing a direct perspective on the morphology and thickness of nearly face-on bars and bulges with integral field unit spectroscopy.Comment: 14 pages, 16 figures. Accepted for publication in Ap

Spectral properties of a two-orbital Anderson impurity model across a non-Fermi liquid fixed point

We study by NRG the spectral properties of a two-orbital Anderson impurity model in the presence of an exchange splitting which follows either regular or inverted Hund's rules. The phase diagram contains a non-Fermi liquid fixed point separating a screened phase, where conventional Kondo effect occurs, from an unscreened one, where the exchange-splitting takes care of quenching the impurity degrees of freedom. On the Kondo screened side close to this fixed point the impurity density of states shows a narrow Kondo-peak on top of a broader resonance. This narrow peak transforms in the unscreened phase into a narrow pseudo-gap inside the broad resonance. Right at the fixed point only the latter survives. The fixed point is therefore identified by a jump of the density of states at the chemical potential. We also show that particle-hole perturbations which simply shift the orbital energies do not wash out the fixed point, unlike those perturbations which hybridize the two orbitals. Consequently the density-of-state jump at the chemical potential remains finite even away from particle-hole symmetry, and the pseudo-gap stays pinned at the chemical potential, although it is partially filled in. We also discuss the relevance of these results for lattice models which map onto this Anderson impurity model in the limit of large lattice-coordination. Upon approaching the Mott metal-insulator transition, these lattice models necessarily enter a region with a local criticality which reflects the impurity non-Fermi liquid fixed point. However, unlike the impurity, the lattice can get rid of the single-impurity fixed-point instability by spontaneously developing bulk-coherent symmetry-broken phases, which we identify for different lattice models.Comment: 43 pages, 11 figures. Minor corrections in the Appendi

Intermediate temperature solid oxide fuel cell/electrolyzer towards future large-scale production

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The role of working memory on dual-task cost during walking performance in childhood

This study examined the effect of a secondary motor task on walking ability, whether performance differed according to age and the possible relationship between cognitive abilities, specifically working memory, and dual-task costs in children with typical development. Fifty-three female children (mean age M = 10 \ub1 2 years), were divided into two different age groups: a young (7\u20139 years; n = 17) and an older group (10\u201313 years; n = 36). First, participants performed a Walking Test (WT) without additional tasks; afterward, they performed the same walking test while performing each of the following tasks: carrying (1) a glass of water, (2) a ball on a round tray and (3) the combination of both tasks (1) and (2). The Test of Memory and Learning were used to assess working memory. WTs under a dual-task condition generally produced worse results compared to a single-task condition [F(3,135) = 32.480, p < 0.001]. No age-related difference was observed [F(1,45) = 0.497, p = 0.485]. Age, digit forward and backward, facial memory, and paired recall accounted altogether for 28.6% of variance in dual-task ability during WT while carrying a glass of water and a ball on a round tray. Specifically, facial memory significantly accounted for the variance of DTC in WTWT (\u3b2 = 120.381, p = 0.016). Moreover, a trend toward a statistical significance was observed for digit forward (\u3b2 = 120.275, p = 0.085). Results underlined that regardless of the age, a dual-task performance might affect walking performance depending on the required secondary task. Moreover, our results showed the association between working memory skills and dual-task cost in walking abilit

Impairment of the autophagic flux in astrocytes intoxicated by trimethyltin

Autophagy is a lysosomal catabolic route for protein aggregates and damaged organelles which in different stress conditions, such as starvation, generally improves cell survival. An impairment of this degradation pathway has been reported to occur in many neurodegenerative processes. Trimethyltin (TMT) is a potent neurotoxin present as an environmental contaminant causing tremors, seizures and learning impairment in intoxicated subjects. The present data show that in rat primary astrocytes autophagic vesicles (AVs) appeared after few hours of TMT treatment. The analysis of the autophagic flux in TMT-treated astrocytes was consistent with a block of the late stages of autophagy and was accompanied by a progressive accumulation of the microtubule associated protein light chain 3 (LC3) and of p62/SQSTM1. Interestingly, an increased immunoreactivity for p62/SQSTM1 was also observed in hippocampal astrocytes detected in brain slices of TMT-intoxicated rats. The time-lapse recordings of AVs in EGFP-mCherry-LC3B transfected astrocytes demonstrated a reduced mobility of autophagosomes after TMT exposure respect to control cells. The observed block of the autophagic flux cannot be overcome by known autophagy inducers such as rapamycin or 0.5mM lithium. Although ineffective when used at 0.5mM, lithium at higher concentrations (2mM) was able to protect astrocyte cultures from TMT toxicity. This effect correlated well with its ability to determine the phosphorylation/inactivation of glycogen kinase synthase-3β (GSK-3β)

A novel fully human antitumour immunoRNase targeting ErbB2-positive tumours

BACKGROUND: ErbB2 is an attractive target for immunotherapy, as it is a tyrosine kinase receptor overexpressed on tumour cells of different origin, with a key role in the development of malignancy. Trastuzumab, the only humanised anti-ErbB2 antibody currently used in breast cancer with success, can engender cardiotoxicity and a high fraction of patients is resistant to Trastuzumab treatment. METHODS: A novel human immunoRNase, called anti-ErbB2 human compact antibody-RNase (Erb-hcAb-RNase), made up of the compact anti-ErbB2 antibody Erbicin-human-compact Antibody (Erb-hcAb) and human pancreatic RNase (HP-RNase), has been designed, expressed in mammalian cell cultures and purified. The immunoRNase was then characterised as an enzymatic protein, and tested for its biological actions in vitro and in vivo on ErbB2-positive tumour cells. RESULTS: Erb-hcAb-RNase retains the enzymatic activity of HP-RNase and specifically binds to ErbB2-positive cells with an affinity comparable with that of the parental Erb-hcAb. Moreover, this novel immunoRNase is endowed with an effective and selective antiproliferative action for ErbB2-positive tumour cells both in vitro and in vivo. Its antitumour activity is more potent than that of the parental Erb-hcAb as the novel immunoconjugate has acquired RNase-based cytotoxicity in addition to the inhibitory growth effects, antibody-dependent and complement-dependent cytotoxicity of Erb-hcAb. CONCLUSION: Erb-hcAb-RNase could be a promising candidate for the immunotherapy of ErbB2-positive tumours

Is the dependence on the temperature of the friction important in stress triggering phenomena? The case of the 2000 Iceland seismic sequence

We perform numerical experiments by using a mass–spring fault model subject to an external coseismic stress perturbation due to a remote seismic event happening on another fault, the causative fault. In particular, the aim of this study is to investigate the instantaneous fault interaction and possible triggering that happens when a fault perturbed by a stress change fails before the so–called unperturbed instability. As a realistic example we focus our attention on the instantaneous dynamic triggering phenomena occurred during the 17 June 2000 south Iceland seismic sequence in the South Iceland Seismic Zone (SISZ, Reykjanes Peninsula). The main event (Ms 6.6) was followed by three large events within a few tens of seconds (8, 26 and 30 s, respectively) located in a neighborhood of several tens of km. Among them the 26 s event was the best constrained (Bizzarri and Belardinelli, 2008). In the present study, conditions to simulate the instantaneous dynamic triggering connected to the former three events, have been investigated using the simple 1–D spring–slider analogue model representing a fault governed by the rate– and state–dependent friction laws. In previous studies suitable constitutive parameters of the modeled fault which allow the instantaneous triggering of the three events, have been found (Antonioli et al., 2006) and, furthermore, it was also shown how the dynamics of the 26 s event strongly depends on the assumed constitutive law and stress conditions (Bizzarri and Belardinelli, 2008) by considering the Dieterich–Ruina (DR henceforth) and the Ruina–Dieterich (RD henceforth) governing laws. In this context take place the present study original contribution that is to better understand if the conditions of instantaneous dynamic triggering (focusing on the case of the 26 s triggered event) provide any significant differences if modeled with a different rate– and state–dependent governing equation, the Chester and Higgs law (CH henceforth; see Chester and Higgs, 1992; Bizzarri, 2010b; Bizzarri, 2010c) which accounts for the thermal effect for frictional heating which may occur during seismic sliding

Time occurrence of earthquake instabilities in rate– and state–dependent friction models

Since the latter half of last century many studies and laboratory experiments have focused on the understanding of the evolution of frictional strength during sliding events on active faults. Such events may occur through aseismic fault creep, high-velocity slip and, in some cases, as a combination of both. According to the concept that earthquakes are frictional instabilities, their time occurrence may show a periodical pattern (the seismic cycle) whose behavior can be referred to the stick-slip dynamic. The dynamic evolution of a fault is often modeled considering its formal analogy with a physical system known as the spring-slider model (namely, a damped harmonic oscillator). Many experimental studies have been conducted using the spring-slider model, most of them simulating the interaction between slip surfaces with the surrounding elastic medium with a single-degree-of-freedom system. Despite its obvious limitations, such a model has provided important insights on dynamics of stick-slip cycle [Gu et al., 1984; Carlson et al., 1994], nucleation of earthquakes and triggered earthquake phenomena [e.g. Belardinelli et al., 2003]. On the basis of several experimental results on rock friction, Dieterich (1979) and Ruina (1983) formulated rate- and state-dependent friction laws, in which the frictional resistance is expressed through the evolution of the sliding rate and its history. Afterwards, Chester and Higgs (1992) figured out that also the temperature variation, produced by frictional heating, can affect the duration of the seismic cycle and the evolution of the frictional strength as well and consequently they incorporate such a thermal effect, improving the previous Ruina’s constitutive law. The present study is aimed to: 1. investigate the spring-slider physical response depending on the adopted constitutive law; 2. show the influence that the constitutive laws can exert on the time occurrence of a seismic instability and on the seismic cycle duration; 3. compare the constitutive laws in order to show their different features in simulating the evolution of slip velocity, stress drop and seismic cycle