Morphological Phase Diagram for Lipid Membrane Domains with Entropic Tension

Circular domains in phase-separated lipid vesicles with symmetric leaflet composition commonly exhibit three stable morphologies: flat, dimpled, and budded. However, stable dimples (i.e., partially budded domains) present a puzzle since simple elastic theories of domain shape predict that only flat and spherical budded domains are mechanically stable in the absence of spontaneous curvature. We argue that this inconsistency arises from the failure of the constant surface tension ensemble to properly account for the effect of entropic bending fluctuations. Formulating membrane elasticity within an entropic tension ensemble, wherein tension represents the free energy cost of extracting membrane area from thermal bending of the membrane, we calculate a morphological phase diagram that contains regions of mechanical stability for each of the flat, dimpled, and budded domain morphologies

The ice-breaker effect: Singing mediates fast social bonding

It has been proposed that singing evolved to facilitate social cohesion. However, it remains unclear whether bonding arises out of properties intrinsic to singing or whether any social engagement can have a similar effect. Furthermore, previous research has used one-off singing sessions without exploring the emergence of social bonding over time. In this semi-naturalistic study, we followed newly formed singing and non-singing (crafts or creative writing) adult education classes over seven months. Participants rated their closeness to their group and their affect, and were given a proxy measure of endorphin release, before and after their class, at three timepoints (months 1, 3 and 7). We show that although singers and non-singers felt equally connected by timepoint 3, singers experienced much faster bonding: singers demonstrated a significantly greater increase in closeness at timepoint 1, but the more gradual increase shown by non-singers caught up over time. This represents the first evidence for an ‘ice-breaker effect’ of singing in promoting fast cohesion between unfamiliar individuals, which bypasses the need for personal knowledge of group members gained through prolonged interaction. We argue that singing may have evolved to quickly bond large human groups of relative strangers, potentially through encouraging willingness to coordinate by enhancing positive affect

Time as a limited resource: Communication Strategy in Mobile Phone Networks

We used a large database of 9 billion calls from 20 million mobile users to examine the relationships between aggregated time spent on the phone, personal network size, tie strength and the way in which users distributed their limited time across their network (disparity). Compared to those with smaller networks, those with large networks did not devote proportionally more time to communication and had on average weaker ties (as measured by time spent communicating). Further, there were not substantially different levels of disparity between individuals, in that mobile users tend to distribute their time very unevenly across their network, with a large proportion of calls going to a small number of individuals. Together, these results suggest that there are time constraints which limit tie strength in large personal networks, and that even high levels of mobile communication do not fundamentally alter the disparity of time allocation across networks.Comment: 10 pages, 3 figures. Accepted for publication in Social Network

Cochlear SGN neurons elevate pain thresholds in response to music.

The C-tactile (CLTM) peripheral nervous system is involved in social bonding in primates and humans through its capacity to trigger the brain’s endorphin system. Since the mammalian cochlea has an unusually high density of similar neurons (type-II spiral ganglion neurons, SGNs), we hypothesise that their function may have been exploited for social bonding by co-opting head movements in response to music and other rhythmic movements of the head in social contexts. Music provides one of many cultural behavioural mechanisms for ‘virtual grooming’ in that it is used to trigger the endorphin system with many people simultaneously so as to bond both dyadic relationships and large groups. Changes in pain threshold across an activity are a convenient proxy assay for endorphin uptake in the brain, and we use this, in two experiments, to show that pain thresholds are higher when nodding the head than when sitting still

UV/IR duality in noncommutative quantum field theory

We review the construction of renormalizable noncommutative euclidean phi(4)-theories based on the UV/IR duality covariant modification of the standard field theory, and how the formalism can be extended to scalar field theories defined on noncommutative Minkowski space.Comment: 12 pages; v2: minor corrections, note and references added; Contribution to proceedings of the 2nd School on "Quantum Gravity and Quantum Geometry" session of the 9th Hellenic School on Elementary Particle Physics and Gravity, Corfu, Greece, September 13-20 2009. To be published in General Relativity and Gravitatio

Influence of Gravity on noncommutative Dirac equation

In this paper, we investigate the influence of gravity and noncommutativity on Dirac equation. By adopting the tetrad formalism, we show that the modified Dirac equation keeps the same form. The only modification is in the expression of the covariant derivative. The new form of this derivative is the product of its counterpart given in curved space-time with an operator which depends on the noncommutative $\theta$-parameter. As an application, we have computed the density number of the created particles in presence of constant strong electric field in an anisotropic Bianchi universe.Comment: 9 pages, correct some miprints, Accepted for publication in journal of Mod. Phys. Letters

Antioxidant activity of extracts from Acanthopanax senticosus

Antioxidants play an important role in inhibiting and scavenging radicals, thus providing protection to humans against infectious and degenerative diseases. Literature shows that the antioxidant activity ishigh in medicinal plants. Realizing the fact that, this study was carried out to determine the antioxidant activity of water extract of Acanthopanax senticosus. Water extract (0.5 g/50 ml) of A. senticosus (ASE) were prepared and total phenol contents (TPC) and radical scavenging activity (RSA) of the extracts was determined for antioxidant activity. The TPC and RSA of ASE were 366.67 M and 67.67%, respectively. In addition, the effect of ASE on DNA damage induced by H2O2 in human lymphocytes was also evaluated by Comet assay. The ASE showed strong inhibitory effect as its concentration increased from 0.125 to 1% by 65 to 81% against DNA damage induced by 200 M of H2O2. These results suggest that water extract of commercial dried A. senticosus for tea showed significant antioxidant activity and protective effect against oxidative DNA damage

Growth Characteristics of Ecotype Superior Line of Bermudagrass and Development of Its rDNA Markers

Interest in turfgrass has steadily increased in Korea since the 2002 Korea-Japan World Cup . Use of zoysiagrass (Zoysia japonica L.) has been limited due to its slow recovery, low shoot density, short green period and low wear tolerance during dormancy (Lee et. al., 1999). Bermudagrass has high quality and fast recovery, but has low cold tolerance (Richardson et. al., 1978). This research compared the growth characteristics of a superior line of bermudagrass, named as Joyspy with other standard cultivars and to develop its rDNA markers

Growth Characteristics of Superior Lines of Zoysia Grass (\u3cem\u3eZoysia Japonica\u3c/em\u3e) And Development of Its DNA Markers

Demand for turf grass has steadily increased for recreation and sport fields after the 2002 Korea-Japan World Cup in Korea. Zoysia grass has the advantage of easy management, including low water and fertiliser requirement, but has limitations such as low recovery, low shoot density and short green period (Kim et al., 1999). Objectives of this research were to select superior lines in the collected clones, compare the superior lines of zoysia grass with other standard cultivars for growth characteristics and to develop the DNA markers of superior lines