5,611 research outputs found
The influence of entrepreneursâ immigrant status and time on the perceived likelihood of exporting
We contribute in this paper to the scant literature on the factors and conditions influencing the development of different perceptions of potential international opportunities for immigrant and native entrepreneurs in the pre-internationalization phase. Specifically, we investigate what factors influence the perceived likelihood entrepreneurs have of exporting. Building on entrepreneurial intentions and opportunity-based entrepreneurial processes, we propose a cognitive account of perceived likelihood of exporting based on entrepreneursâ perceptions of the desirability and feasibility of export opportunities. We investigate how the immigrant status (i.e., individual characteristics) and time (i.e., contextual factors) influence the relationship between the desirability and feasibility of exporting, and entrepreneursâ perceived likelihood of exporting. We employ an experimental design on a matched-pair sample of 108 native and immigrant entrepreneurs in domestic technology-based firms. The results are a unique account of the cognitive antecedents of the perceived likelihood of exporting under different temporal conditions, comparing immigrant and native entrepreneurs. We discuss theoretical and practical implications
VISTO: An open-source device to measure exposure time in psychological experiments
The study of higher cognitive processes often relies on the manipulation of bottom-up stimulus characteristics such as exposure time. While several software exist that can schedule the onset and offset time of a visual stimulus, the actual exposure time depends on several factors that are not easy to control, resulting in undesired variability within and across studies. Here we present VISTO, a simple device built on the Arduino platform that allows one to measure the exact onset and offset of a visual stimulus, and to test its synchronization with a trigger signal. The device is used to measure the profile of luminance waveforms in arbitrary analog/digital (AD) units, and the implications of these luminance profiles are discussed based on a model of information accumulation from visual exposure. Moreover, VISTO can be calibrated to match the brightness of each experimental monitor. VISTO allows for control of stimulus timing presentation, both in classical laboratory settings and in more complex settings as technology allows to use new display devices or acquisition equipment. In sum, VISTO allows one to: âą measure the profile of luminance curves. âą determine the exposure time of a visual stimulus. âą measure the synchronization between a trigger signal and a visual stimulus
Daily earthquake forecasts during the May-June 2012 Emilia earthquake sequence (northern Italy)
The paper has no abstrac
) a swarm at Strandline Lake, which continued for several years (1996-1999); and (5) deformation of Mt. Peulik (inflation begins after October
Abstract In the fall of 1996 the Alaska Volcano Observatory recorded an unprecedented level of seismic and volcanic activity. The following were observed: (1) a swarm at Iliamna Volcano (August 1996 to mid-1997); (2) an eruption at Pavlof Volcano (September 1996 to December 1996; (3) a swarm at Martin/Mageik volcanoes (October 1996); (4) a swarm at Strandline Lake, which continued for several years (1996)(1997)(1998)(1999); and (5) deformation of Mt. Peulik (inflation begins after October 1996 and ends in fall 1998), based on interpretation of interferometric synthetic aperture radar data. The number of monitored volcanic areas in 1996 was thirteen. We conducted two formal statistical tests to determine the likelihood of four of these events occurring randomly in the same time interval. The tests are based on different conceptual probabilistic models (classical and Bayesian) that embrace a wide range of realistic tectonic models. The first test considered only the areas in which swarms or eruptions occurred (7 of 13 if Strandline Lake is included; 6 of 12 otherwise), by comparing the real catalog with 10,000 synthetic catalogs under the assumption that the sites are independent. The second method is a hierarchical Bayesian model in which the probability of a swarm at each of the 13 (or 12) areas is different but the parent population is the same. We found that the likelihood of the swarms and eruption occurring nearly simultaneously by chance alone is small for a wide range of probabilistic schemes and, consequently, for different tectonic scenarios. Therefore, we conclude that the events may be related to a single process. We speculate that a widespread deformation pulse or strain transient occurred, mainly in the east half of the arc, and may be the most likely candidate for causing such nearly simultaneous events
Response of microchannel plates to single particles and to electromagnetic showers
We report on the response of microchannel plates (MCPs) to single
relativistic particles and to electromagnetic showers. Particle detection by
means of secondary emission of electrons at the MCP surface has long been
proposed and is used extensively in ion time-of-flight mass spectrometers. What
has not been investigated in depth is their use to detect the ionizing
component of showers. The time resolution of MCPs exceeds anything that has
been previously used in calorimeters and, if exploited effectively, could aid
in the event reconstruction at high luminosity colliders. Several prototypes of
photodetectors with the amplification stage based on MCPs were exposed to
cosmic rays and to 491 MeV electrons at the INFN-LNF Beam-Test Facility. The
time resolution and the efficiency of the MCPs are measured as a function of
the particle multiplicity, and the results used to model the response to
high-energy showers.Comment: Paper submitted to NIM
Response of microchannel plates in ionization mode to single particles and electromagnetic showers
Hundreds of concurrent collisions per bunch crossing are expected at future
hadron colliders. Precision timing calorimetry has been advocated as a way to
mitigate the pileup effects and, thanks to their excellent time resolution,
microchannel plates (MCPs) are good candidate detectors for this goal. We
report on the response of MCPs, used as secondary emission detectors, to single
relativistic particles and to electromagnetic showers. Several prototypes, with
different geometries and characteristics, were exposed to particle beams at the
INFN-LNF Beam Test Facility and at CERN. Their time resolution and efficiency
are measured for single particles and as a function of the multiplicity of
particles. Efficiencies between 50% and 90% to single relativistic particles
are reached, and up to 100% in presence of a large number of particles. Time
resolutions between 20ps and 30ps are obtained.Comment: 20 pages, 9 figures. Paper submitted to NIM
Reaching activity in parietal area V6A of macaque: eye influence on arm activity or retinocentric coding of reaching movements?
Parietal area V6A contains neurons modulated by the direction of gaze as well as neurons able to code the direction of arm movement. The present study was aimed to disentangle the gaze effect from the effect of reaching activity upon single V6A neurons. To this purpose, we used a visuomotor task in which the direction of arm movement remained constant while the animal changed the direction of gaze. Gaze direction modulated reach-related activity in about two-thirds of tested neurons. In several cases, modulations were not due to the eye-position signal per se, the apparent eye-position modulation being just an epiphenomenon. The real modulating factor was the location of reaching target with respect to the point gazed by the animal, that is, the retinotopic coordinates towards which the action of reaching occurred. Comparison of neural discharge of the same cell during execution of foveated and non-foveated reaching movements, performed towards the same or different spatial locations, confirmed that in a part of V6A neurons reaching activity is coded retinocentrically. In other neurons, reaching activity is coded spatially, depending on the direction of reaching movement regardless of where the animal was looking at. The majority of V6A reaching neurons use a system that encompasses both of these reference frames. These results are in line with the view of a progressive visuomotor transformation in the dorsal visual stream, that changes the frame of reference from the retinocentric one, typically used by the visual system, to the arm-centred one, typically used by the motor system
- âŠ