A computerized Langmuir probe system

For low pressure plasmas it is important to record entire single or double Langmuir probe characteristics accurately. For plasmas with a depleted high energy tail, the accuracy of the recorded ion current plays a critical role in determining the electron temperature. Even for high density Maxwellian distributions, it is necessary to accurately model the ion current to obtain the correct electron density. Since the electron and ion current saturation values are, at best, orders of magnitude apart, a single current sensing resistor cannot provide the required resolution to accurately record these values. We present an automated, personal computer based data acquisition system for the determination of fundamental plasma properties in low pressure plasmas. The system is designed for single and double Langmuir probes, whose characteristics can be recorded over a bias voltage range of ±70 V with 12 bit resolution. The current flowing through the probes can be recorded within the range of 5 nA–100 mA. The use of a transimpedance amplifier for current sensing eliminates the requirement for traditional current sensing resistors and hence the need to correct the raw data. The large current recording range is realized through the use of a real time gain switching system in the negative feedback loop of the transimpedance amplifier

TEMPERATURE-DEPENDENCE OF DOMAIN-WALL COERCIVE FIELD IN MAGNETIC GARNET-FILMS

The coercive properties of magnetically uniaxial liquid-phase epitaxy garnet films were investigated between 10 K and the Neel temperature (T(N) less-than-or-equal-to 500 K). Two independent methods, the results of which are nearly identical (magnetical response of oscillating domain walls and the method of coercive loops measured in a vibrating sample magnetometer), were used. Besides the usual domain-wall coercive field, H(dw), the critical coercive pressure, p(dw), was also introduced as it describes in a direct way the interactions of the domain walls with the wall-pinning traps. Both H(dw) and p(dw) were found to increase exponentially with decreasing temperature. Three different types of wall-pinning traps were identified in the sample and their strength, their rate of change with temperature, and their temperature range of activity were determined

SURVEY OF THE DEPENDENCE ON TEMPERATURE OF THE COERCIVITY OF GARNET-FILMS

The temperature dependence of the domain-wall coercive field of epitaxial magnetic garnets films has been investigated in the entire temperature range of the ferrimagnetic phase, and has been found to be described by a set of parametric exponents. In subsequent temperature regions different slopes were observed, with breaking points whose position was found to be sample dependent. A survey ba.ed on literature Data as well as on a large number of our own samples shows the general existence of this piecewise exponential dependence and the presence of the breaking points. This type of domain-wall coercive field temperature dependence was found in all samples in the large family of the epitaxial garnets (about 30 specimens of more than ten chemical compositionsj and also in another strongly anisotropic material (TbFeCo)

Tobacco advertising, promotion, and sponsorship (TAPS) in Ethiopia: a scoping review and narrative synthesis

# Background Tobacco advertising, promotion and sponsorship (TAPS) has been shown to increase tobacco use in both adults and young people. In Ethiopia, TAPS is recognised as a top priority for the government, and all tobacco advertising, promotion, and sponsorship forms are prohibited. There is recognition that there are gaps in the evidence needed to inform policy and practice on TAPS, but the extent and nature of these gaps have not been explored. This review was aimed at understanding the extent and nature of the evidence gaps on TAPS in Ethiopia and identifying primary research priorities to inform future research direction. # Methods Systematic searches were conducted in February 2022 in the following research databases: Medline, EMBASE, and PsycInfo. Two reviewers independently screened the study reports for eligibility and extracted data from the eligible studies. The extracted data was collated and summarised descriptively and policy, practice, and research recommendations were drawn. Research topics on TAPS in Ethiopia that stakeholders perceived to be priorities for primary research were identified through a consultation workshop. # Results 579 research reports were identified, and only six studies were included in the scoping review. The included studies explored the following topics: the use of tobacco imagery in movies/films (two studies); the association between mass media exposure or home internet access and tobacco use (two studies), watching of televised football and tobacco smoking in adolescents (one study), exposure to point-of-sale advertising of tobacco products and daily occurrence of smoking or second-hand smoke exposure in the home among women (one study), and exposure to anti-smoking messages through mass media and disparities in risk perceptions across socio-economic and urban-rural subgroups (one study). None of the included studies investigated tobacco-related sponsorship. The top research priority topics identified by stakeholders in Ethiopia were: 1) barriers and facilitators to TAPS policy implementation, enforcement, and compliance monitoring; and 2) developing and testing effective, low-cost, and scalable strategies for TAPS enforcement and compliance monitoring. # Conclusions There is a need for research evidence to inform policy and practice on TAPS in Ethiopia, particularly on barriers and facilitators to TAPS policy implementation, enforcement, compliance monitoring, and effective, low-cost, and scalable strategies for TAPS enforcement and compliance monitoring

Constraint on axial-vector meson mixing angle from nonrelativistic constituent quark model

In a nonrelativistic constituent quark model we find a constraint on the mixing angle of the strange axial-vector mesons, $35^o\stackrel{<}{\sim } \theta _K\stackrel{<}{\sim }55^o,$ determined solely by two parameters: the mass difference of the $a_1$ and $b_1$ mesons and the ratio of the constituent quark masses.Comment: 8 pages, LaTe

Symmetry Decomposition of Chaotic Dynamics

Discrete symmetries of dynamical flows give rise to relations between periodic orbits, reduce the dynamics to a fundamental domain, and lead to factorizations of zeta functions. These factorizations in turn reduce the labor and improve the convergence of cycle expansions for classical and quantum spectra associated with the flow. In this paper the general formalism is developed, with the $N$-disk pinball model used as a concrete example and a series of physically interesting cases worked out in detail.Comment: CYCLER Paper 93mar01

Structural optimization incorporating centrifugal and Coriolis effects

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76888/1/AIAA-10798-921.pd

Properties of the Strange Axial Mesons in the Relativized Quark Model

We studied properties of the strange axial mesons in the relativized quark model. We calculated the $K_1$ decay constant in the quark model and showed how it can be used to extract the $K_1 (^3P_1) - K_1 (^1P_1)$ mixing angle ($\theta_K$) from the weak decay $\tau \to K_1 \nu_\tau$. The ratio $BR(\tau \to \nu_\tau K_1 (1270))/BR(\tau\to \nu_\tau K_1(1400))$ is the most sensitive measurement and also the most reliable since the largest of the theoretical uncertainties factor out. However the current bounds extracted from the TPC/Two-Gamma collaboration measurements are rather weak: we typically obtain $-30^o \lesssim \theta_K \lesssim 50^o$ at 68\% C.L. We also calculated the strong OZI-allowed decays in the pseudoscalar emission model and the flux-tube breaking model and extracted a $^3P_1 - ^1P_1$ mixing angle of $\theta_K \simeq 45^o$. Our analysis also indicates that the heavy quark limit does not give a good description of the strange mesons.Comment: Revised version to be published in Phys. Rev. D. Minor changes. Latex file uses revtex version 3 and epsfig, 4 postcript figures are attached. The full postcript version with embedded figures is available at ftp://ftp.physics.carleton.ca/pub/theory/godfrey/ocipc9512.ps.

Academic Functioning and Mental Health in Adolescence

The current study examines patterns of academic functioning and mental health in 184 middle school children and the relation of such patterns to their prior and subsequent functioning. Data were collected from children during their second, third, fourth, eighth, and ninth grade school years. Cluster analyses were used to delineate patterns of academic functioning and mental health during eighth grade. The authors examined the relation of these patterns to academic functioning and mental health 1 year later the transition to high school, and then examined the long-term developmental roots of the eighth grade patterns using data collected during elementary school years. Results indicated variegated patterns of academic and emotional functioning at eighth grade and stability in these patterns across the high school transition. Some long-term continuity was found among children showing uniformly positive or negative functioning at eighth grade. Studying child functioning across multiple domains and time periods is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68127/2/10.1177_0743558499142002.pd

Measurement of the hadronic photon structure function F_{2}^{γ} at LEP2

The hadronic structure function of the photon F_{2}^{γ} (x, Q²) is measured as a function of Bjorken x and of the photon virtuality Q² using deep-inelastic scattering data taken by the OPAL detector at LEP at e⁺e⁻ centre-of-mass energies from 183 to 209 GeV. Previous OPAL measurements of the x dependence of F_{2}^{γ} are extended to an average Q² of 〈Q²〉=780 GeV² using data in the kinematic range 0.15<x<0.98. The Q² evolution of F_{2}^{γ} is studied for 12.1<〈Q²〉<780 GeV² using three ranges of x. As predicted by QCD, the data show positive scaling violations in F_{2}^{γ} with F_{2}^{γ} (Q²)/α = (0.08±0.02⁺⁰·⁰⁵_₀.₀₃) + (0.13±0.01⁺⁰·⁰¹_₀.₀₁) lnQ², where Q² is in GeV², for the central x region 0.10–0.60. Several parameterisations of F_{2}^{γ} are in qualitative agreement with the measurements whereas the quark-parton model prediction fails to describe the data