Point-contact tunneling spectroscopy measurement of Cux_xTiSe2_2: disorder-enhanced Coulomb effects

We performed point-contact spectroscopy tunneling measurements on Cu$_x$TiSe$_2$ bulk with $x=0.02$ and $0.06$ at temperatures ranging from $T=4-40$ K and observe a suppression in the density of states around zero-bias that we attribute to enhanced Coulomb interactions due to disorder. We find that the correlation gap associated with this suppression is related to the zero-temperature resistivity. We use our results to estimate the disorder-free transition temperature and find that the clean limit $T_{c0}$ is close to the experimentally observed $T_c$.Comment: 4 pages, 4 figure

Heme oxygenase-2 gene deletion attenuates oxidative stress in neurons exposed to extracellular hemin

BACKGROUND: Hemin, the oxidized form of heme, accumulates in intracranial hematomas and is a potent oxidant. Growing evidence suggests that it contributes to delayed injury to surrounding tissue, and that this process is affected by the heme oxygenase enzymes. In a prior study, heme oxygenase-2 gene deletion increased the vulnerability of cultured cortical astrocytes to hemin. The present study tested the effect of HO-2 gene deletion on protein oxidation, reactive oxygen species formation, and cell viability after mixed cortical neuron/astrocyte cultures were incubated with neurotoxic concentrations of hemin. RESULTS: Continuous exposure of wild-type cultures to 1–10 μM hemin for 14 h produced concentration-dependent neuronal death, as detected by both LDH release and fluorescence intensity after propidium iodide staining, with an EC(50 )of 1–2 μM; astrocytes were not injured by these low hemin concentrations. Cell death was consistently reduced by at least 60% in knockout cultures. Exposure to hemin for 4 hours, a time point that preceded cell lysis, increased protein oxidation in wild-type cultures, as detected by staining of immunoblots for protein carbonyl groups. At 10 μM hemin, carbonylation was increased 2.3-fold compared with control sister cultures subjected to medium exchanges only; this effect was reduced by about two-thirds in knockout cultures. Cellular reactive oxygen species, detected by fluorescence intensity after dihydrorhodamine 123 (DHR) staining, was markedly increased by hemin in wild-type cultures and was localized to neuronal cell bodies and processes. In contrast, DHR fluorescence intensity in knockout cultures did not differ from that of sham-washed controls. Neuronal death in wild-type cultures was almost completely prevented by the lipid-soluble iron chelator phenanthroline; deferoxamine had a weaker but significant effect. CONCLUSIONS: These results suggest that HO-2 gene deletion protects neurons in mixed neuron-astrocyte cultures from heme-mediated oxidative injury. Selective inhibition of neuronal HO-2 may have a beneficial effect after CNS hemorrhage

Digital Participation and Risk Contexts in Journalism Education

High school journalism programs nurture student voice, information literacy, and collaboration. Journalism programs do not merely produce commodities; they help students constitute a public within a school community. When publishing online, student journalists navigate relationships behind the scenes with stakeholders, including peers, adults, and the institution. Publishing can be fraught with hesitation and fear of consequences for speaking out. Because of this implication, journalism programs can serve as “potentially valuable yet imperfect” settings for the amplification of student voice and civic development, but can also unduly limit students’ self-expression, especially for girls (Bobkowski & Belmas, 2017). What might be the affordances and constraints of digital participation in a high school journalism program? How might youth journalists and other participants navigate exigencies of publishing online in this context? We, the head editors and adviser, use grounded theory to examine processes and develop pragmatic knowledge (Glaser & Strauss, 2017). Through a mix of prompts, group interviews, and participant observation, we develop a case study that demonstrates implications for ‘risk context,’ or the total situation of an actor’s vulnerability brought on by digital participation in publishing online. We describe what digital participation is good for, and for whom, thus further theorizing relationships between agency and co-production

The Phase Behavior of Mixed Lipid Membranes in Presence of the Rippled Phase

We propose a model describing liquid-solid phase coexistence in mixed lipid membranes by including explicitly the occurrence of a rippled phase. For a single component membrane, we employ a previous model in which the membrane thickness is used as an order parameter. As function of temperature, this model properly accounts for the phase behavior of the three possible membrane phases: solid, liquid and the rippled phase. Our primary aim is to explore extensions of this model to binary lipid mixtures by considering the composition dependence of important model parameters. The obtained phase diagrams show various liquid, solid and rippled phase coexistence regions, and are in quantitative agreement with the experimental ones for some specific lipid mixtures.Comment: 8pages, 5figure

Anisotropic Inflation in a 5D Standing Wave Braneworld and Dimensional Reduction

We investigate a cosmological solution within the framework of a 5D standing wave braneworld model generated by gravity coupled to a massless scalar phantom-like field. By obtaining a full exact solution of the model we found a novel dynamical mechanism in which the anisotropic nature of the primordial metric gives rise to i) inflation along certain spatial dimensions, and ii) deflation and a shrinking reduction of the number of spatial dimensions along other directions. This dynamical mechanism can be relevant for dimensional reduction in string and other higher dimensional theories in the attempt of getting a 4D isotropic expanding space-time.Comment: 8 pages in Late

Group Decision Support Systems for Emergency Management and Resilience: CoastalProtectSIM

This paper introduces the concept of Group Decision Support Systems (GDSS) as a tool to support emergency management in coastal cities. As an illustration of the potential value of GDSS, we discuss the use of CoastalProtectSIM, a simulation model that can be a valuable GDSS tool, particularly in the mitigation stages of the emergency management cycle. We present preliminary results from the use of the simulation environment in a graduate course. We finish the paper by presenting our experience as a framework for building more efficient and secure emergency management systems through the use of GDSS