Increased motility impedes clustering

We study interacting run and tumble particles in two dimensions, both on a lattice and in continuum, where particles move in the direction of their internal orientation. These motile particles can tumble and change their internal orientation with a fixed rate $\omega;$ $\omega^{-1}$ quantifies the motility. Starting from interacting particle systems that exhibit phase separation transitions in the absence of motility, we ask how the ordering in the system changes when motility is added and increased. We observe that increased motility impedes cluster formation in a large class of models including conserved lattice gas, driven lattice gas, and interacting hard-disc models in continuum, and explain why. We further show that a stable phase-separated state is ruled out in the absence of any attractive interaction.Comment: 9 pages, 21 figure

Polarization fluctuation dominated electrical transport processes of polymer based ferroelectric-field-effect transistors

Ferroelectric field-effect transistors (FE-FETs) consisting of tunable dielectric layers are utilized to investigate interfacial transport processes. Large changes in the dielectric constant as a function of temperature are observed in FE-FETs in conjunction with the ferroelectric to paraelectric transition. The devices offer a test bed to evaluate specific effects of polarization on the electrical processes. FE-FETs have dominant contributions from polarization-fluctuation rather than static dipolar disorder prevalent in high k paraelectric dielectric-based FETs. Additionally, photo-excitation measurements in the depletion mode reveal clear features in the FET response at different temperatures, indicative of different transport regimes.Comment: 6 figure

Ascertaining women’s preferred mode of address and preferred choice of title during pregnancy and childbirth

To determine how women in pregnancy would like to be addressed and to ascertain their preferred choice of title during pregnancy. A questionnaire was administered to 925 antenatal women. Midwifery and medical staff (183) were invited to respond to a similar questionnaire.The response rate was 71.2% from the survey of pregnant women. The vast majority (82.1%) preferred to be addressed by their first name. Women were in favour of being called ’patient’ (32.8%) as their first choice. The staff survey yielded a response rate of 77%. The majority (81.8%) of health professionals preferred to address women by their first name. ’Mother’ (28.7%) was the most popular first choice. We conclude that women in pregnancy do have a preference on how they would like to be addressed and this is predominantly by first name. Health professionals also prefer to call pregnant women by their first name. The term ’patient’ was the most popular first choice of title of women in pregnancy but the term ’mother’ was the preferred choice of the health professionals. Medical staff were more likely to choose ’patient’ than midwives

Design of a Low Offset, Low Noise Amplifier for Neural Recording Applications

The design of a capacitive feedback based neural recording amplifier is presented. The prime design requirements in case of neural amplifiers includes low noise, high gain, high CMRR, low power, low area and low offset voltage. However, there is an inherent trade-off between noise-power and area-offset in the design process which needs to be addressed. A Recycling Folded Cascode based Operational Transconductance Amplifier (RFC-OTA) topology is employed to realize the amplifier as it offers better gain and offset voltage as compared to other topologies. The sizing of the transistors has been done with the primary objective of low random offset voltage while meeting other design criteria within the specified range subject to all inherent trade-offs. Simulations have been done in Cadence Virtuoso using SCL 180 nm technology and comparative analysis with other reported designs reveals that the proposed RFC-OTA based neural amplifier design achieves a low random offset voltage of 1.4 mV with a low input noise of 1.38 µV as compared to most of the reported design

Volume preserving multidimensional integrable systems and Nambu--Poisson geometry

In this paper we study generalized classes of volume preserving multidimensional integrable systems via Nambu--Poisson mechanics. These integrable systems belong to the same class of dispersionless KP type equation. Hence they bear a close resemblance to the self dual Einstein equation. All these dispersionless KP and dToda type equations can be studied via twistor geometry, by using the method of Gindikin's pencil of two forms. Following this approach we study the twistor construction of our volume preserving systems

Chaperone-like activity of tubulin

Tubulin, a ubiquitous protein of eukaryotic cytoskeleton, is a building block unit of microtubule. Although several cellular processes are known to be mediated through the tubulin-microtubule system, the participation of tubulin or microtubule in protein folding pathway has not yet been reported. Here we show that goat brain tubulin has some functions and features similar to many known molecular chaperones. Substoichiometric amounts of tubulin can suppress the non-thermal and thermal aggregation of a number of unrelated proteins such as insulin, equine liver alcohol dehydrogenase, and soluble eye lens proteins containing β- and γ-crystallins. This chaperone-like activity of tubulin becomes more pronounced as temperature increases. Aging of tubulin solution at 37° C also enhances its chaperone-like activity. Tubulin loses its chaperone-like activity upon removal of its flexible hydrophilic C-terminal tail. These results suggest that both electrostatic and hydrophobic interactions are important in substrate binding by tubulin and that the negatively charged C-terminal tails play a crucial role for its chaperone-like activity

Measurement and Modeling of Infrared Nonlinear Absorption Coefficients and Laser-induced Damage Thresholds in Ge and GaSb

Using a simultaneous fitting technique to extract nonlinear absorption coefficients from data at two pulse widths, we measure two-photon and free-carrier absorption coefficients for Ge and GaSb at 2.05 and 2.5 μm for the first time, to our knowledge. Results agreed well with published theory. Single-shot damage thresholds were also measured at 2.5 μm and agreed well with modeled thresholds using experimentally determined parameters including nonlinear absorption coefficients and temperature dependent linear absorption. The damage threshold for a single-layer Al2O3 anti-reflective coating on Ge was 55% or 35% lower than the uncoated threshold for picosecond or nanosecond pulses, respectively