2,620 research outputs found
The EEOC and Immigrant Workers
This lecture describes how the EEOC continues to represent immigrant workers in an extremely challenging climate of xenophobia
Numerical Simulation of Nano Scanning in Intermittent-Contact Mode AFM under Q control
We investigate nano scanning in tapping mode atomic force microscopy (AFM)
under quality (Q) control via numerical simulations performed in SIMULINK. We
focus on the simulation of whole scan process rather than the simulation of
cantilever dynamics and the force interactions between the probe tip and the
surface alone, as in most of the earlier numerical studies. This enables us to
quantify the scan performance under Q control for different scan settings.
Using the numerical simulations, we first investigate the effect of elastic
modulus of sample (relative to the substrate surface) and probe stiffness on
the scan results. Our numerical simulations show that scanning in attractive
regime using soft cantilevers with high Qeff results in a better image quality.
We, then demonstrate the trade-off in setting the effective Q factor (Qeff) of
the probe in Q control: low values of Qeff cause an increase in tapping forces
while higher ones limit the maximum achievable scan speed due to the slow
response of the cantilever to the rapid changes in surface profile. Finally, we
show that it is possible to achieve higher scan speeds without causing an
increase in the tapping forces using adaptive Q control (AQC), in which the Q
factor of the probe is changed instantaneously depending on the magnitude of
the error signal in oscillation amplitude. The scan performance of AQC is
quantitatively compared to that of standard Q control using iso-error curves
obtained from numerical simulations first and then the results are validated
through scan experiments performed using a physical set-up
Entropy Production of Brownian Macromolecules with Inertia
We investigate the nonequilibrium steady-state thermodynamics of single
Brownian macromolecules with inertia under feedback control in isothermal
ambient fluid. With the control being represented by a velocity-dependent
external force, we find such open systems can have a negative entropy
production rate and we develop a mesoscopic theory consistent with the second
law. We propose an equilibrium condition and define a class of external forces,
which includes a transverse Lorentz force, leading to equilibrium.Comment: 10 pages, 1 figur
Calidad percibida del deporte escolar como predictor del abandono deportivo en adolescentes
X-linked retinoschisis in three females from the same family: A phenotype-genotype correlation
Purpose: To describe the clinical findings and outcome for three homozygous females affected with X-linked retinoschisis (XLRS) in a large Colombian family with 26 affected males. Methods: Retrospective review of charts for females from a family with XLRS who underwent complete ophthalmologic examinations, ancillary tests, clinical genetic evaluation, and molecular studies. Results: Three female patients (6 eyes) with clinical findings of XLRS were identified. The patients' ages ranged from 10 to 37 years. Initial visual acuity was equal to or worse than 20/50 in 4 eyes (66%) of 2 patients. Four eyes (66%) were hyperopic. Intraocular pressure was normal in all eyes. Three eyes (50%) had cataracts, and vitreous veils were present in 3 (50%). The optic disk was pale in 6 eyes (100%). Foveal schisis was present in 6 eyes (100%). Peripheral retinal schisis was present in five eyes. A silvery gloss or tapetal-like retinal reflex or sheen was observed in 6 eyes (100%), and dendritic lines were found in 2 (33%). One eye had a retinal break, and one had a retinal detachment. Two eyes underwent cataract extraction; one patient underwent bilateral cryotherapy, one, laser treatment, and one, scleral buckling. Final visual acuity was 20/50 to 20/100 in 2 eyes and 20/200 to 20/400 in 4. Follow-up ranged from 7 to 22 years. Molecular analysis showed that all three female patients were homozygous for the allele 639delG of (on) the XRLS1 gene. Conclusions: Compared with their affected male relatives, three females from a family with XLRS had similar ocular findings and a more severe course of disease. These findings are explained by the fact that these patients were homozygous for a mutation in the XLRS1 gene
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