640 research outputs found
The Internationalization of Science and its Influence on Academic Entrepreneurship
We conjecture that the mobility of academic scientists increases the propensity of such agents to engage in academic entrepreneurship. Our empirical analysis is based on a survey of researchers at the Max Planck Society in Germany. We find that mobile scientists are more likely to become nascent entrepreneurs. Thus, it appears that citizenship and foreign-education are important determinants of the early stages of academic entrepreneurship.Academic Entrepreneurship, Human Capital, Scientific Mobility, Knowledge Transfer, Immigrant Entrepreneurship
Geometrical jitter and bolometric regime in photon detection by straight superconducting nanowire
We present a direct observation of the geometrical jitter in single photon
detection by a straight superconducting nanowire. Differential measurement
technique was applied to the 180-{\mu}m long nanowire similar to those commonly
used in the technology of superconducting nanowire single photon detectors
(SNSPD). A non-gaussian geometrical jitter appears as a wide almost uniform
probability distribution (histogram) of the delay time (latency) of the
nanowire response to detected photon. White electrical noise of the readout
electronics causes broadened, Gaussian shaped edges of the histogram.
Subtracting noise contribution, we found for the geometrical jitter a standard
deviation of 8.5 ps and the full width at half maximum (FWHM) of the
distribution of 29 ps. FWHM corresponds to the propagation speed of the
electrical signal along the nanowire of m/s or 0.02 of the
speed of light. Alternatively the propagation speed was estimated from the
central frequency of the measured first order self-resonance of the nanowire.
Both values agree well with each other and with previously reported values. As
the intensity of the incident photon flux increases, the wide probability
distribution collapses into a much narrower Gaussian distribution with a
standard deviation dominated by the noise of electronics. We associate the
collapse of the histogram with the transition from the discrete, single photon
detection to the uniform bolometric regim
Magnetic hysteresis effects in superconducting coplanar microwave resonators
We performed transmission spectroscopy experiments on coplanar half
wavelength niobium resonators at a temperature T=4.2 K. We observe not only a
strong dependence of the quality factor Q and the resonance frequency f_res on
an externally applied magnetic field but also on the magnetic history of our
resonators, i.e. on the spatial distribution of trapped Abrikosov vortices in
the device. We find these results to be valid for a broad range of frequencies
and angles between the resonator plane and the magnetic field direction as well
as for resonators with and without antidots near the edges of the center
conductor and the ground planes. In a detailed analysis we show, that
characteristic features of the experimental data can only be reproduced in
calculations, if a highly inhomogeneous rf-current density and a flux density
gradient with maxima at the edges of the superconductor is assumed. We
furthermore demonstrate, that the hysteretic behaviour of the resonator
properties can be used to considerably reduce the vortex induced losses and to
fine-tune the resonance frequency by the proper way of cycling to a desired
magnetic field
The internationalization of science and its influence on academic entrepreneurship
We conjecture that the mobility of academic scientists increases the propensity of such agents to engage in academic entrepreneurship. Our empirical analysis is based on a survey of researchers at the Max Planck Society in Germany. We find that mobile scientists are more likely to become nascent entrepreneurs. Thus, it appears that citizenship and foreign-education are important determinants of the early stages of academic entrepreneurship
UVOT Measurements of Dust and Star Formation in the SMC and M33
When measuring star formation rates using ultraviolet light, correcting for
dust extinction is a critical step. However, with the variety of dust
extinction curves to choose from, the extinction correction is quite uncertain.
Here, we use Swift/UVOT to measure the extinction curve for star-forming
regions in the SMC and M33. We find that both the slope of the curve and the
strength of the 2175 Angstrom bump vary across both galaxies. In addition, as
part of our modeling, we derive a detailed recent star formation history for
each galaxy.Comment: 6 pages, 5 figures, conference proceedings from Swift: 10 years of
Discovery, held in Rome (2-5 Dec. 2014
Feuersalamander - Salamandra salamandra
Der Feuersalamander (Salamandra salamandra) ist eine von 18 in Sachsen vorkommenden Amphibienarten. Dieser Schwanzlurch kann etwa 20 cm lang werden und ist mit seiner gelben Flecken- oder Streifenzeichnung auf schwarzem Grund unverwechselbar. Diese signalisiert seinen Feinden, dass er nicht genießbar ist, denn auf seiner Haut befinden sich Drüsen, aus denen er das Gift Samandarin absondert. Deshalb haben erwachsene Feuersalamander auch kaum Feinde. In Gefangenschaft können die Tiere über 50 Jahre alt werden. Jeder Salamander besitzt ein individuelles Fleckenmuster und so kann man die Lurche in freier Wildbahn über lange Zeit beobachten. Bereits bei den mit Büschelkiemen ausgestatteten Larven kann man an jedem Beinansatz einen gelben Fleck erkennen, was sie von den sehr ähnlichen Molchlarven unterscheidet.
Zur besseren Abschätzung des Gesamtvorkommens sowie von Rückgangs- bzw. Verlustursachen werden zurzeit alle potenziellen Lebensräume sowie frühere Fundorte auf das aktuelle Vorkommen der Art überprüft. Hierfür brauchen wir Ihre Mithilfe. Wenn Sie Feuersalamander oder deren Larven entdeckt haben, dann schreiben Sie uns Ihre Beobachtung mit Anzahl, Ort, Datum sowie Fundumstände bzw. Verhalten, wenn möglich mit Foto, per Post oder E-Mail an: Sächsisches Landesamt für Umwelt, Landwirtschaft und Geologie, Ref. 62 Artenschutz, Stichwort „Feuersalamander“, Pillnitzer Platz 3, 01326 Dresden
oder per E-Mail an: [email protected]
Redaktionsschluss: 29.08.201
Timing jitter in photon detection by straight superconducting nanowires: Effect of magnetic field and photon flux
We studied the effect of the external magnetic field and photon flux on
timing jitter in photon detection by straight superconducting NbN nanowires. At
two wavelengths 800 and 1560 nm, statistical distribution in the appearance
time of the photon count exhibits Gaussian shape at small times and exponential
tail at large times. The characteristic exponential time is larger for photons
with smaller energy and increases with external magnetic field while variations
in the Gaussian part of the distribution are less pronounced. Increasing photon
flux drives the nanowire from quantum detection mode to the bolometric mode
that averages out fluctuations of the total number of nonequilibrium electrons
created by the photon and drastically reduces jitter. The difference between
Gaussian parts of distributions for these two modes provides the measure for
the electron-number fluctuations. Corresponding standard deviation increases
with the photon energy. We show that the two-dimensional hot-spot detection
model explains qualitatively the effect of magnetic field
Assessing Post-Operative Complications in Pediatric Cochlear Implant Surgery
Cochlear implantation (CI) surgery is the standard of care treatment for pediatric patients diagnosed with severe-to-profound sensorineural hearing loss. There is compelling evidence that supports the use of CIs to improve hearing, language comprehension, and speech development significantly in children of all ages. While the operation is considered relatively safe, invasive procedures involving the skull can put patients at risk of adverse events.
This study aims to help pediatric otolaryngologists identify high risk patients and take preventative measures to ensure minimal complications.
The specific objectives include the following:
1) To determine the incidence of postoperative complications in pediatric patients undergoing CI surgery.
2) To identify the risk factors associated with postoperative complications in pediatric CI surgery
3) To perform a sub-analysis of complication rates among different pediatric age cohorts.
A full-text retrospective chart review was conducted for all pediatric patients that underwent CI surgery at Children’s Hospital of Michigan between August 2016 and June 2021. This cohort study included 72 patients that were presented to this urban pediatric surgery unit. Each patient\u27s comorbidities and complications were then classified as a qualitative variable and SPSS was used to investigate the statistical significance between these variables and demographics such as age cohorts, and postoperative complication risk was calculated using Pearson Chi Squared testing. As surgical techniques, medical devices, and patient guidelines continue to evolve, new data is necessary to understand how complication rates change over time. Pediatric otolaryngologists must be knowledgeable about evidence-based risk factors and complication rates related to CI surgery
- …