A micro-electro-mechanical-system-based thermal shear-stress sensor with self-frequency compensation

By applying the micro-electro-mechanical-system (MEMS) fabrication technology, we developed a micro-thermal sensor to measure surface shear stress. The heat transfer from a polysilicon heater depends on the normal velocity gradient and thus provides the surface shear stress. However, the sensitivity of the shear-stress measurements in air is less than desirable due to the low heat capacity of air. A unique feature of this micro-sensor is that the heating element, a film 1 µm thick, is separated from the substrate by a vacuum cavity 2 µm thick. The vacuum cavity prevents the conduction of heat to the substrate and therefore improves the sensitivity by an order of magnitude. Owing to the low thermal inertia of the miniature sensing element, this shear-stress micro-sensor can provide instantaneous measurements of small-scale turbulence. Furthermore, MEMS technology allows us make multiple sensors on a single chip so that we can perform distributed measurements. In this study, we use multiple polysilicon sensor elements to improve the dynamic performance of the sensor itself. It is demonstrated that the frequency-response range of a constant-current sensor can be extended from the order of 100 Hz to 100 kHz

Criterion for bosonic superfluidity in an optical lattice

We show that the current method of determining superfluidity in optical lattices based on a visibly sharp bosonic momentum distribution $n({\bf k})$ can be misleading, for even a normal Bose gas can have a similarly sharp $n({\bf k})$. We show that superfluidity in a homogeneous system can be detected from the so-called visibility $(v)$ of $n({\bf k})$ $-$ that $v$ must be 1 within $O(N^{-2/3})$, where $N$ is the number of bosons. We also show that the T=0 visibility of trapped lattice bosons is far higher than what is obtained in some current experiments, suggesting strong temperature effects and that these states can be normal. These normal states allow one to explore the physics in the quantum critical region.Comment: 4 pages, 2 figures; published versio

Double Phase Transitions in Magnetized Spinor Bose-Einstein Condensation

It is investigated theoretically that magnetized Bose-Einstein condensation (BEC) with the internal (spin) degrees of freedom exhibits a rich variety of phase transitions, depending on the sign of the interaction in the spin channel. In the antiferromagnetic interaction case there exist always double BEC transitions from single component BEC to multiple component BEC. In the ferromagnetic case BEC becomes always unstable at a lower temperature, leading to a phase separation. The detailed phase diagram for the temperature vs the polarization, the spatial spin structure, the distribution of non-condensates and the excitation spectrum are examined for the harmonically trapped systems.Comment: 6 pages, 7 figures. Submitted to J. Phys. Soc. Jp

A survey of the treatment and management of patients with severe chronic spontaneous urticaria.

Chronic spontaneous urticaria (CSU) is characterized by the recurrent appearance of weals, angio‐oedema or both, occurring at least twice weekly for longer than 6 weeks.1 It is often managed with antihistamines, but occasionally requires other systemic agents in recalcitrant cases. A cross‐sectional survey was conducted by means of an internet‐based survey tool (Typeform; https://www.typeform.com). Participating consultants with a specialist interest in urticaria were identified through the specialist registers of the British Society of Allergy and Clinical Immunology (BSACI), the Improving Quality in Allergy Services (IQAS) Group and the British Association of Dermatologists (BAD), and invited to take part. The survey content was based on current CSU treatment guidelines from EAACI/GA2LEN/EDF/WAO1 and the British Society for Allergy and Clinical Immunology (BSACI).2 The EAACI/GA2LEN/EDF/WAO guidelines are a joint initiative of the Dermatology Section of the European Academy of Allergy and Clinical Immunology (EAACI), the Global Allergy and Asthma European Network (GA2LEN) (a European Union‐funded network of excellence), the European Dermatology Forum (EDF), and the World Allergy Organization (WAO). To standardize responses, all participants were presented with a case of recalcitrant CSU (failed on maximum dose of nonsedating antihistamines and montelukast), requiring alternative systemic treatment. Questions covered usage of systemic treatments, routine disease severity assessments, adherence to treatment guidelines and perceived barriers to prescribing. Responses (Table 1) were received from 19 UK consultants (26 surveys sent; completion rate 73%), 15 of whom had > 10 years’ experience in the treatment of CSU. The majority were allergy (58%) and dermatology consultants (37%). Of the 19 consultants, 56% provide a dedicated urticaria service, 37% treat both adult and paediatric patients, and the majority (79%) use systemic medications other than antihistamines and montelukast. Omalizumab and ciclosporin were the most commonly used first‐line agents (47% and 27% respectively) (Fig. 1). The majority (84%) of consultants use validated measures to assess disease severity, including the weekly Urticaria Activity Score (UAS‐7, 63%), the Physician Global Assessment (63%), the Patient Global Assessment (44%) and the Dermatology Quality of Life Index (DLQI) (38%). Guidelines are used by 89% to direct their management of CSU, with 50% using the EAACI/GA2LEN/EDF/WAO guideline,1 compared with 31% primarily using the BSACI guideline.2 The main perceived barriers to prescribing systemic medications were potential adverse effects (AEs) (32% strongly agreed), potential long‐term toxicity (26% strongly agreed), cost of treatment (42% strongly agreed), and views expressed by the patient and their family (37% agreed)

Examining the quality of adolescent–parent relationships among Chilean families

The purpose of this study was to examine if adolescents reports of warm and harsh parenting practices by their mothers and fathers varied as a function of demographic, youth and their mothers or mother figures' individual and family characteristics. Data are from 707 community-dwelling adolescents (mean age=14, SD=1.4) and their mothers or mother figures in Santiago, Chile. Having a warmer relationship with both parents was inversely associated with the adolescents' age and positively associated with adolescents' family involvement and parental monitoring. Both mothers' and fathers' harsh parenting were positively associated with adolescent externalizing behaviors and being male and inversely associated with youth autonomy and family involvement. These findings suggest that net of adolescent developmental emancipation and adolescent behavioral problems, positive relationships with parents, especially fathers, may be nurtured through parental monitoring and creation of an interactive family environment, and can help to foster positive developmental outcomes.http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC3839673&blobtype=pdfAccepted manuscrip

Virtual Topology Design for Minimizing Network Diameter and Average Hop Count in WDM Networks

We design virtual topologies in wavelength division multiplexing (WDM) networks to minimize the network diameter and average hop count, where network diameter refers to the number of hops of the longest shortest path and average hop count is the average number of hops among the shortest paths of all node pairs. Such objectives are important to WDM networks, especially to those with statistical multiplexing mechanisms such as optical burst switching (OBS) and optical packet switching (OPS). By minimizing the network diameter and average hop count, optical packets or bursts will experience less contention loss and smaller delay due to a reduced number of intermediate nodes en route. In this paper, we first formulate an integer linear program (ILP) for optimal design of virtual topologies with minimized network diameter and average hop count. Then, a novel heuristic least weight minimum diameter (LWMD) is proposed to find good solutions efficiently. Based on the virtual topology obtained, we further design two traffic accommodation schemes to provision wavelengths under a given traffic matrix, with guaranteed network diameter and minimized network resource consumption.published_or_final_versio

Assessing the Dynamic Relationship Between Small and Large Cap Stock Prices

The historical long-run return on small capitalization stocks has unquestionably outperformed large capitalization stocks since 1926. The phenomenon of small capitalization stocks having higher risk- adjusted returns compared with large capitalization stocks is an equity market anomaly first discovered in 1981. Since then, many academics and investors have strongly argued that “size is dead”. This paper argues that far from being dead, the phenomenon of size effect appears alive and well and it could be exploited effectively over long-term investment horizons. To analyze this phenomenon, we focus specifically on the dynamics of small cap and large cap prices. We test for multivariate cointegration among the small cap and large cap stock prices and other major macroeconomic factors from 1980 to 2006. After conducting robustness tests on forward recursive and ten year rolling samples, we find evidence of one long- run cointegrating vector. Of more importance, there is a consistently negative and highly significant relationship between small and large cap stock prices. This could suggest that the size effect exhibits a cyclical pattern. Our analysis also provides supporting evidence that the size effect appears to exhibit predictable reversals when considering long investment horizons. Furthermore, we demonstrate how small cap stocks can be viewed as less risky than large cap stocks over long holding periods. Finally, we make suggestions on how asset managers and individual investors can enhance returns based on our overall results

Crystalline electric field effects in the electrical resistivity of PrOs4_4Sb12_{12}

The temperature $T$ and magnetic field $H$ dependencies of the electrical resistivity $\rho$ of the recently discovered heavy fermion superconductor \PrOsSb{} have features that are associated with the splitting of the Pr$^{3+}$ Hund's rule multiplet by the crystalline electric field (CEF). These features are apparently due to magnetic exchange and aspherical Coulomb scattering from the thermally populated CEF-split Pr$^{3+}$ energy levels. The $\rho(T)$ data in zero magnetic field can be described well by calculations based on CEF theory for various ratios of magnetic exchange and aspherical Coulomb scattering, and yield CEF parameters that are qualitatively consistent with those previously derived from magnetic susceptibility, specific heat, and inelastic neutron scattering measurements. Calculated $\rho(H)$ isotherms for a $\Gamma_{3}$ ground state qualitatively account for the `dome-shaped' feature in the measured $\rho(H)$ isotherms.Comment: 8 pages, 2 figures, submitted to Journal of Physics: Condensed Matte

Quantum Hall Ferromagnets

It is pointed out recently that the $\nu=1/m$ quantum Hall states in bilayer systems behave like easy plane quantum ferromagnets. We study the magnetotransport of these systems using their ``ferromagnetic" properties and a novel spin-charge relation of their excitations. The general transport is a combination of the ususal Hall transport and a time dependent transport with $quantized$ time average. The latter is due to a phase slippage process in $spacetime$ and is characterized by two topological constants. (Figures will be provided upon requests).Comment: 4 pages, Revtex, Ohio State Universit

Lowest Open Channels, Bound States, and Narrow Resonances of Dipositronium

The constraints imposed by symmetry on the open channels of dipositronium has been studied, and the symmetry-adapted lowest open channel of each quantum state has been identified. Based on this study, the existence of two more 0^+ bound states has been theoretically confirmed, and a 0^+ narrow resonance has been predicted. A variational calculation has been performed to evaluate the critical strength of the repulsive interaction . Two 0^- states are found to have their critical strengths very close to 1, they are considered as candidates of new narrow resonances or loosely bound states .Comment: 10 pages, 0 figure