15,460 research outputs found
Printed circuit board with bellows rivet connection Patent
Electrical connection for printed circuits on common board, using bellows principle in rive
EXAMINING THE RELATIONSHIP BETWEEN GENETIC COUNSELORS’ IMPLICIT ATTITUDES TOWARD DISABILITY AND THEIR PRACTICE METHODS
Genetic counselors serve as a link between the medical community and the disability community as they are regularly the first exposure families have following a new diagnosis in a pregnancy, infant or child. This role requires genetic counselors to be responsible and compassionate when approaching conversations about disability. With a lack of research on how the specific attitudes of genetic counselors toward disability impact clinical practice, we aimed to understand these attitudes, what factors affect implicit attitudes toward disability, and how these attitudes affect counseling. Case scenarios involving disability were used to examine different counseling content preferences within a genetic counseling session including medical and diagnostic information, lifestyle and social implications, psychosocial issues. Attitudes were measured using the Disability Implicit Association Test (DA-IAT), and personal and professional experience with disability was assessed. Results from the study reveal that genetic counselors have a stronger bias toward ability compared to the previous participants of the DA-IAT. Results reassure that personal experience with individuals with disabilities does not significantly impact DA-IAT scores or preferred counseling methods. The uniform bias observed across specialties may point to an underlying characteristic of the genetic counseling field either due to shared exposure to disability, self-selection or another factor still undetermined, but even more likely, may point to an inability of the available tool to assess implicit bias toward and individual or group of individuals
Characteristics of traveling-wave tubes with periodic circuits
An analysis of an electron beam which interacts with a chain of coupled resonators is presented. Several important characteristics of traveling-wave tubes which employ periodic slow-wave circuits are described. It is found that, even for a lossless circuit, the gain does not become large near either pass band edge although the interaction impedance does become very large. Furthermore, useful amplification is found to occur outside the normal circuit pass band, particularly when the frequency is below the low-frequency cutoff where the circuit presents an inductive reactance to the beam. The problem of matching uniform transmission lines to the periodic circuit is discussed from the equivalent circuit point of view and it is shown that the terminating impedance which produces no reflection from the output end of the circuit when the beam is present may be appreciably different from that required when the beam is absent. The method of analysis applies to spatial harmonic operation, including backward spatial harmonics, as well as to synchronously tuned multicavity klystrons
Traveling-Wave Couplers for Longitudinal Beam-Type Amplifiers
The equations governing traveling-wave interaction between an electron beam and a slow-wave circuit are formulated in terms of amplitudes of circuit mode and slow and fast space charge modes. The resulting equations are solved to find expressions for the matrix which relates the mode amplitudes at the output of the traveling-wave coupler to the mode amplitudes at the input. The properties of this matrix are discussed and numerical values given for Kompfner Dip. Matrices for velocity jumps and drift regions are also given, and the characteristics of couplers which are preceded by or followed by a drift region and velocity jump are discussed. It is shown that necessary and sufficient conditions for the removal of beam noise from the fast space-charge wave by any lossless coupler are that, for a circuit input, there be no circuit output (M11 = 0) and no slow space-charge wave output (M21 = 0). These results are then applied to the design of fast space-charge wave couplers for longitudinal beam type parametric amplifiers
Thermal Fluctuations: Modes versus the Continuum
The thermal fluctuation spectrum of the signal received on a patch electrode is examined and it is shown that the spectrum shows both the modes of the plasma and a continuous spectrum related to the independent-particle motions of plasma electrons. Modes whose axial phase velocity are more than 3–4 times the electron thermal speed are lightly Landau-damped and are clearly separated from the continuum. Long wavelength modes are "acoustic" in nature. If the axial phase velocity of a mode becomes less than 1–2 times the electron thermal speed, then the mode becomes strongly Landau-damped and it merges into the continuum. The mode velocities are of the order of wpa , where a is the plasma radius, so that the plasma radius must be at least several deBye lengths in order to have lightly damped modes. In general, the spectrum is a mixture of a continuous spectrum together with a finite number of modes which are Landau-damped by varying amounts, depending on their phase velocity relative to the electron thermal speed. Only in the extreme limit, wpa << vth does the continuous spectrum tend to a Gaussian of width k vth, characteristic of independent particles. The effect of the "load impedance" on the measurements is also discussed
Thermal excitation of modes in a non-neutral plasma
We examine theoretically the thermal fluctuations in a non-neutral plasma, as observed on a segmented electrode surrounding the plasma, using the Nyquist theorem. The fluctuation spectrum is peaked at frequencies which correspond to modes of the plasma. Measurement of these fluctuations and of the input admittance of the plasma in the vicinity of one of the mode resonances can be used to give a completely experimental, and non-destructive, measurement of the plasma temperature. Since some of the modes are negative energy modes and exhibit negative absorption due to the plasma rotation, a direct application of the Nyquist theorems will not give correct results for the non-axisymmetric modes. This problem is circumvented by first calculating the fluctuations in a frame rotating with the plasma and transforming to the laboratory frame. This results in a modification of Nyquist's theorem. Measurement issues are discussed
Dynamics of non-neutral plasmas
In this paper the focus is on the dynamics of two-dimensional cylindrical non-neutral plasmas. After reviewing some highlights of the non-neutral plasma dynamics, some recent two-dimensional results are described: vortex dynamics, diocotron instabilities of hollow profiles, collisionless damping of modes and fluid trapping by modes, fluid echoes, the cyclotron center of mass modes and warm plasma Bernstein modes, and temperature determination from fluctuation measurements. Attention is called to some unsolved problems
Animal cell cytokinesis: the role of dynamic changes in the plasma membrane proteome and lipidome
In animal cells, cytokinesis is characterised by the formation of the mitotic spindle that signals the assembly of an actomyosin ring between the spindle poles. Contraction of this ring drives ingression of the cleavage furrow, and culminates in the formation of a thin intercellular bridge between the daughter cells. At the centre of this bridge is the midbody, which is thought both to provide a site of attachment for the plasma membrane furrow and act as foci for the spatial and temporal control mechanisms that drive abscission. This review will focus upon recent studies that offer new insight into these events, in particular studies that elaborate on the mechanism of attachment between the furrow plasma membrane and the underlying cytoskeleton, and how dynamic changes in membrane composition might underpin key aspects of cytokinesis
FACTORS AFFECTING U.S. DEMAND FOR REDUCED-FAT FLUID MILK
U.S. fluid milk consumption has changed dramatically since the early 1970s. Whole milk accounted for over 81% of commercial fluid milk disappearance in 1970. By 1993, this percentage was less than 39%. A three-equation fluid milk demand system is estimated for fluid milks that vary by fat content. The household panel data set used includes over 4,300 households that recorded fluid milk purchased for at-home consumption over a 12-month period. Given that many of these households did not consume one or more of the three milk types, the econometric model explicitly incorporates the censored nature of these commodity demands. Own- and cross-price and substitution estimated along with effects of household demographic characteristics.Demand and Price Analysis,
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