2,557 research outputs found
Encountered Problems and Outcome Status in Nascent Entrepreneurship
The relationship is investigated between outcome status and encountered problems in the business start-up process. Contrary to expectations, we find that starters do not differ from quitters in number and type of problems encountered, and that problems encountered generally do not affect outcome status. This Dutch research uses a design that is comparable to the U.S. PSED (Panel Study of Entrepreneurial Dynamics) in which a sample of 414 nascent entrepreneurs were followed over a three year period.encountered-problems;nascent-entrepreneurship;outcome-status
The “broken escalator” phenomenon: Vestibular dizziness interferes with locomotor adaptation
BACKGROUND: Although vestibular lesions degrade postural control we do not know the relative contributions of the magnitude of the vestibular loss and subjective vestibular symptoms to locomotor adaptation. OBJECTIVE: To study how dizzy symptoms interfere with adaptive locomotor learning. METHODS: We examined patients with contrasting peripheral vestibular deficits, vestibular neuritis in the chronic stable phase (n = 20) and strongly symptomatic unilateral Meniere’s disease (n = 15), compared to age-matched healthy controls (n = 15). We measured locomotor adaptive learning using the “broken escalator” aftereffect, simulated on a motorised moving sled. RESULTS: Patients with Meniere’s disease had an enhanced “broken escalator” postural aftereffect. More generally, the size of the locomotor aftereffect was related to how symptomatic patients were across both groups. Contrastingly, the degree of peripheral vestibular loss was not correlated with symptom load or locomotor aftereffect size. During the MOVING trials, both patient groups had larger levels of instability (trunk sway) and reduced adaptation than normal controls. CONCLUSION: Dizziness symptoms influence locomotor adaptation and its subsequent expression through motor aftereffects. Given that the unsteadiness experienced during the “broken escalator” paradigm is internally driven, the enhanced aftereffect found represents a new type of self-generated postural challenge for vestibular/unsteady patients
Encountered Problems and Outcome Status in Nascent Entrepreneurship
The relationship is investigated between outcome status and encountered problems in the business start-up process. Contrary to expectations, we find that starters do not differ from quitters in number and type of problems encountered, and that problems encountered generally do not affect outcome status. This Dutch research uses a design that is comparable to the U.S. PSED (Panel Study of Entrepreneurial Dynamics) in which a sample of 414 nascent entrepreneurs were followed over a three year period
Nonlinear Transport in a Quantum Point Contact due to Soft Disorder Induced Coherent Mode Mixing
We show that the coherent mixing of different transverse modes, due to
forward scattering of carriers by soft impurity- or boundary potentials leads
to a nonlinear, asymmetric current response of quantum point contacts (QPC).
The oscillating contribution to the current is sensitive both to driving
voltage and to gate voltage in direct analogy to the electrostatic
Aharonov-Bohm effect.
Our calculations are in a good agreement with recent experimental data
showing small-scale conductivity nonlinearities and asymmetry in QPC.Comment: 4 pages, 2 figures (availiable upon request), REVTEX, Applied Physics
Report 93-4
Treatment of lung disease in alpha-1 antitrypsin deficiency: a systematic review - Supplementary Material
Research data used in the paper 'Treatment of lung disease in alpha-1 antitrypsin deficiency: a systematic review.', Edgar RG, Patel M, Bayliss S, Crossley D, Sapey E, Turner AM, forthcoming in The International Journal of Chronic Obstructive Pulmonary Disease (2017
Long-term follow-up of intratympanic methylprednisolone versus gentamicin in patients with unilateral Menière’s disease
Objectives: To determine whether long term (>48 months)
symptomatic vertigo control is sustained in patients with
Menie`re’s disease from a previous comparative trial of
intratympanic methylprednisolone versus gentamicin, and if the two treatments remain nonsignificantly different at longterm follow-up.
Study Design: Mail survey recording vertigo frequency in
the previous one and six months, further intratympanic
treatment received, and validated symptom questionnaires.
Setting: Outpatient hospital clinic setting.
Patients: Adult patients with definite unilateral refractory Menie`re’s disease, who previously received in tratympanic treatment in a comparative trial.
Intervention: A survey of trial participants who received
intratympanic gentamicin (40 mg/mL) or methylprednisolone
(62.5 mg/mL).
Outcome measures: Primary: number of vertigo attacks in
the 6 months prior to receiving this survey compared with
the 6 months before the first trial injection.
Secondary: : Number of vertigo attacks over the previous 1 month; validated symptom questionnaire scores of tinnitus, dizziness, vertigo, aural fullness, and functional disability.
Results: Average follow-up was 70.8 months (standard
deviation 17.0) from the first treatment injection. Vertigo attacks in the 6 months prior to receiving the current survey reduced by 95% compared to baseline in both drug groups (intention-to-treat analysis, both p<0.001). No significant difference between drugs was found for the primary and secondary outcomes. Eight participants (methylprednisolone ÂĽ 5 and gentamicin ÂĽ 3) required further injections for relapse after completing the original trial.
Conclusion: Intratympanic methylprednisolone treatment provides effective long-lasting relief of vertigo, without the known inner-ear toxicity associated with gentamicin. There are no significant differences between the two treatments at long term follow-up
Statistics of Coulomb blockade peak spacings for a partially open dot
We show that randomness of the electron wave functions in a quantum dot
contributes to the fluctuations of the positions of the conductance peaks. This
contribution grows with the conductance of the junctions connecting the dot to
the leads. It becomes comparable with the fluctuations coming from the
randomness of the single particle spectrum in the dot while the Coulomb
blockade peaks are still well-defined. In addition, the fluctuations of the
peak spacings are correlated with the fluctuations of the conductance peak
heights.Comment: 13 pages, 1 figur
Finite temperature effects in Coulomb blockade quantum dots and signatures of spectral scrambling
The conductance in Coulomb blockade quantum dots exhibits sharp peaks whose
spacings fluctuate with the number of electrons. We derive the
temperature-dependence of these fluctuations in the statistical regime and
compare with recent experimental results. The scrambling due to Coulomb
interactions of the single-particle spectrum with the addition of an electron
to the dot is shown to affect the temperature-dependence of the peak spacing
fluctuations. Spectral scrambling also leads to saturation in the temperature
dependence of the peak-to-peak correlator, in agreement with recent
experimental results. The signatures of scrambling are derived using discrete
Gaussian processes, which generalize the Gaussian ensembles of random matrices
to systems that depend on a discrete parameter -- in this case, the number of
electrons in the dot.Comment: 14 pages, 4 eps figures included, RevTe
- …