Validating Perception and Use of Mobile Social Network Service: A Cross-Cultural Comparison Study

The rapid developments of Social Network Services (SNS) and mobile technology have offered opportunities to revisitseminal theories of technology use in today’s socio-technical environment. Mobile technology based SNSprovides various service channels that are highly correlated with their respective service contexts, in which culturalinfluences are omnipresent. Investigating use intention in a cross-cultural mobile SNS study implies new theoreticaldiscoveries and managerial practices. This research in progress (RIP) paper suggests that important distinctions existbetween U.S. and Chinese SNS subscribers in terms of SNS use and perceptions. Taking the perspective of SNSusers, we strive to explore the effects of cultural factors (e.g., collectivism vs. individualism) on trust formulation,degree of social awareness, and privacy concern. We examine the antecedents and consequences of legacyconstructs (e.g., technology acceptance and social capital) in SNS. This paper describes the research design to testthe research hypotheses. A triangulation methodology (i.e., qualitative and quantitative methods) is desired andproposed in the design. A discussion of research implications and business practices is also included in this RIPpaper

Cyclic peptides as inhibitors of amyloid fibrillation

Biophysical Structural Chemistr

A dopaminergic switch for fear to safety transitions

Overcoming aversive emotional memories requires neural systems that detect when fear responses are no longer appropriate so that they can be extinguished. The midbrain ventral tegmental area (VTA) dopamine system has been implicated in reward and more broadly in signaling when a better-than-expected outcome has occurred. This suggests that it may be important in guiding fear to safety transitions. We report that when an expected aversive outcome does not occur, activity in midbrain dopamine neurons is necessary to extinguish behavioral fear responses and engage molecular signaling events in extinction learning circuits. Furthermore, a specific dopamine projection to the nucleus accumbens medial shell is partially responsible for this effect. In contrast, a separate dopamine projection to the medial prefrontal cortex opposes extinction learning. This demonstrates a novel function for the canonical VTA-dopamine reward system and reveals opposing behavioral roles for different dopamine neuron projections in fear extinction learning

The cosmic history of hot gas cooling and radio active galactic nucleus activity in massive early-type galaxies

We study the X-ray properties of 393 optically selected early-type galaxies (ETGs) over the redshift range of z≈ 0.0–1.2 in the Chandra Deep Fields (CDFs). To measure the average X-ray properties of the ETG population, we use X-ray stacking analyses with a subset of 158 passive ETGs (148 of which were individually undetected in X-ray). This ETG subset was constructed to span the redshift ranges of z= 0.1–1.2 in the ≈4 Ms CDF-South and ≈2 Ms CDF-North and z= 0.1–0.6 in the ≈250 ks Extended-CDF-South where the contribution from individually undetected active galactic nuclei (AGN) is expected to be negligible in our stacking. We find that 55 of the ETGs are detected individually in X-ray, and 12 of these galaxies have properties consistent with being passive hot-gas-dominated systems (i.e. systems not dominated by an X-ray bright AGN). On the basis of our analyses, we find little evolution in the mean 0.5–2 keV to B-band luminosity ratio (LX/LB∝ [1 +z]1.2) since z≈ 1.2, implying that some heating mechanism prevents the gas from cooling in these systems. We consider that feedback from radio-mode AGN activity could be responsible for heating the gas. We select radio AGN in the ETG population using their far-infrared/radio flux ratio. Our radio observations allow us to constrain the duty cycle history of radio AGN activity in our ETG sample. We estimate that if scaling relations between radio and mechanical power hold out to z≈ 1.2 for the ETG population being studied here, the average mechanical power from AGN activity is a factor of ≈1.4–2.6 times larger than the average radiative cooling power from hot gas over the redshift range z≈ 0–1.2. The excess of inferred AGN mechanical power from these ETGs is consistent with that found in the local Universe for similar types of galaxies

Human lysozyme inhibits the in vitro aggregation of A beta peptides, which in vivo are associated with Alzheimer's disease

Biophysical Structural Chemistr

The Uncertainty in Newton's Constant and Precision Predictions of the Primordial Helium Abundance

The current uncertainty in Newton's constant, G_N, is of the order of 0.15%. For values of the baryon to photon ratio consistent with both cosmic microwave background observations and the primordial deuterium abundance, this uncertainty in G_N corresponds to an uncertainty in the primordial 4He mass fraction, Y_P, of +-1.3 x 10^{-4}. This uncertainty in Y_P is comparable to the effect from the current uncertainty in the neutron lifetime, which is often treated as the dominant uncertainty in calculations of Y_P. Recent measurements of G_N seem to be converging within a smaller range; a reduction in the estimated error on G_N by a factor of 10 would essentially eliminate it as a source of uncertainty in the calculation of the primordial 4He abundance.Comment: 3 pages, no figures, fixed typos, to appear in Phys. Rev.

Magnetotunneling Between Two-dimensional Electron Gases in InAs-AlSb-GaSb Heterostructures

We have observed that the tunneling magnetoconductance between two-dimensional (2D) electron gases formed at nominally identical InAs-AlSb interfaces most often exhibits two sets of Shubnikov-de Haas oscillations with almost the same frequency. This result is explained quantitatively with a model of the conductance in which the 2D gases have different densities and can tunnel between Landau levels with different quantum indices. When the epitaxial growth conditions of the interfaces are optimized, the zero-bias magnetoconductance shows a single set of oscillations, thus proving that the asymmetry between the two electron gases can be eliminated.Comment: RevTeX format including 4 figures; submit for publicatio

Nuclear dependence coefficient α(A,qT)\alpha(A,q_T) for the Drell-Yan and J/ψ\psi production

Define the nuclear dependence coefficient $\alpha(A,q_T)$ in terms of ratio of transverse momentum spectrum in hadron-nucleus and in hadron-nucleon collisions: $\frac{d\sigma^{hA}}{dq_T^2}/ \frac{d\sigma^{hN}}{dq_T^2}\equiv A^{\alpha(A,q_T)}$. We argue that in small $q_T$ region, the $\alpha(A,q_T)$ for the Drell-Yan and J/$\psi$ production is given by a universal function:\ $a+b q_T^2$, where parameters a and b are completely determined by either calculable quantities or independently measurable physical observables. We demonstrate that this universal function $\alpha(A,q_T)$ is insensitive to the A for normal nuclear targets. For a color deconfined nuclear medium, the $\alpha(A,q_T)$ becomes strongly dependent on the A. We also show that our $\alpha(A,q_T)$ for the Drell-Yan process is naturally linked to perturbatively calculated $\alpha(A,q_T)$ at large $q_T$ without any free parameters, and the $\alpha(A,q_T)$ is consistent with E772 data for all $q_T$.Comment: latex, 28 pages, 10 figures, updated two figures, and add more discussion

Application of time-dependent density functional theory to optical activity

As part of a general study of the time-dependent local density approximation (TDLDA), we here report calculations of optical activity of chiral molecules. The theory automatically satisfies sum rules and the Kramers-Kronig relation between circular dichroism and optical rotatory power. We find that the theory describes the measured circular dichroism of the lowest states in methyloxirane with an accuracy of about a factor of two. In the chiral fullerene C_76 the TDLDA provides a consistent description of the optical absorption spectrum, the circular dichroism spectrum, and the optical rotatory power, except for an overall shift of the theoretical spectrum.Comment: 17 pages and 13 PostScript figure