3,247 research outputs found
Manipulating Memory Associations Changes Decision-making Preferences in a Preconditioning Task
Memories of past experiences can guide our decisions. Thus, if memories are undermined or distorted, decision making should be affected. Nevertheless, little empirical research has been done to examine the role of memory in reinforcement decision-making . We hypothesized that if memories guide choices in a conditioning decision-making task, then manipulating these memories would result in a change of decision preferences to gain reward. We manipulated participants’ memories by providing false feedback that their memory associations were wrong before they made decisions that could lead them to win money . Participants’ memory ratings decreased significantly after receiving false feedback. More importantly, we found that false feedback led participants’ decision bias to disappear after their memory associations were undermined . Our results suggest that reinforcement decision-making can be altered by fasle feedback on memories . The results are discussed using memory mechanisms such as spreading activation theories
Fixed export costs and multi-product firms
This paper has two aims. First, we uncover some salient components of fixed export costs, which play a crucial role in recent heterogeneous firms models of international trade. Second, we investigate whether the importance of these fixed export costs varies with the size of a firms export product portfolio. We find that a destination country's institutional quality, such as the quality of regulation or the extent of corruption, form important impediments to a firm's export decision, lowering the export probability by up to 10%-points. Moreover, relative to single-product firms, multi-product firms experience additional export probability decreases of around 2%-points
Teaching science and technology at primary school level: theoretical and practical considerations for primary school teachers' professional training.
This paper focuses on the importance of starting science and technology education at a young age and at the consequential importance of providing primary school teachers with enough professional background to be able to effectively incorporate science and technology into their teaching. We will discuss a large-scale program in The Netherlands that is aimed at the professionalization of elementary school teachers in the field of science and technology. Theoretical and practical considerations will be provided for the three pillars that ideally should be included in teacher training programs in this domain: (1) Primary school teachers’ knowledge of and competency in scientific concepts and scientific reasoning; (2) Primary school teachers’ attitude towards science (in terms of cognitive, affective, and behavioural dimensions of attitude); and (3) Primary school teachers’ pedagogical competency to enhance inquiry-based learning
Early components of the human vestibulo-ocular response to head rotation: latency and gain
To characterize vestibulo-ocular reflex (VOR) properties in the time
window in which contributions by other systems are minimal, eye movements
during the first 50-100 ms after the start of transient angular head
accelerations ( approximately 1000 degrees /s(2)) imposed by a torque
helmet were analyzed in normal human subjects. Orientations of the head
and both eyes were recorded with magnetic search coils (resolution,
approximately 1 min arc; 1000 samples/s). Typically, the first response to
a head perturbation was an anti-compensatory eye movement with zero
latency, peak-velocity of several degrees per second, and peak excursion
of several tenths of a degree. This was interpreted as a passive
mechanical response to linear acceleration of the orbital tissues caused
by eccentric rotation of the eye. The response was modeled as a damped
oscillation (approximately 13 Hz) of the orbital contents, approaching a
constant eye deviation for a sustained linear acceleration. The subsequent
compensatory eye movements showed (like the head movements) a linear
increase in velocity, which allowed estimates of latency and gain with
linear regressions. After appropriate accounting for the preceding passive
eye movements, average VOR latency (for pooled eyes, directions, and
subjects) was calculated as 8.6 ms. Paired comparisons between the two
eyes revealed that the latency for the eye contralateral to the direction
of head rotation was, on average, 1.3 ms shorter than for the ipsilateral
eye. This highly significant average inter-ocular difference was
attributed to the additional internuclear abducens neuron in the pathway
to the ipsilateral eye. Average acceleration gain (ratio between slopes of
eye and head velocities) over the first 40-50 ms was approximately 1.1.
Instantaneous velocity gain, calculated as Veye(t)/Vhead(t-latency),
showed a gradual build-up converging toward unity (often after a slight
overshoot). Instantaneous acceleration gain also converged toward unity
but showed a much steeper build-up and larger oscillations. This behavior
of acceleration and velocity gain could be accounted for by modeling the
eye movements as the sum of the passive response to the linear
acceleration and the active rotational VOR. Due to the latency and the
anticompensatory component, gaze stabilization was never complete. The
influence of visual targets was limited. The initial VOR was identical
with a distant target (continuously visible or interrupted) and in
complete darkness. A near visual target caused VOR gain to rise to a
higher level, but the time after which the difference between far and near
targets emerged varied between individuals
Atom lithography without laser cooling
Using direct-write atom lithography, Fe nanolines are deposited with a pitch
of 186 nm, a full width at half maximum (FWHM) of 50 nm, and a height of up to
6 nm. These values are achieved by relying on geometrical collimation of the
atomic beam, thus without using laser collimation techniques. This opens the
way for applying direct-write atom lithography to a wide variety of elements.Comment: 7 pages, 11 figure
Hotspot Zuidplaspolder: Climate adaptation in the Zuidplaspolder
Building at the lowest point in the Netherlands, in the Zuidplaspolder, is viewed as a challenge and not something that is impossible. The Xplorelab approach in the Hotspot Zuidplaspolder project is a combination of research, implementation of ideas into inspiring examples and evaluation
Deceleration and electrostatic trapping of OH radicals
A pulsed beam of ground state OH radicals is slowed down using a Stark
decelerator and is subsequently loaded into an electrostatic trap.
Characterization of the molecular beam production, deceleration and trap
loading process is performed via laser induced fluorescence detection inside
the quadrupole trap. Depending on details of the trap loading sequence,
typically OH () radicals are trapped at a density
of around cm and at temperatures in the 50-500 mK range. The 1/e
trap lifetime is around 1.0 second.Comment: 4 pages, 3 figure
Estimate of halo ellipticity as a function of radius with flexions
The cold dark matter theory predicts triaxial dark matter haloes. The radial
distribution of halo ellipticity depends on baryonic processes and the nature
of dark matter particles (collisionless or collisional). Here we show that we
can use lensing flexion ratios to measure the halo ellipticity as a function of
radius. We introduce a weight function and study the relationship between the
first and second order statistics of flexion ratios, both of which can be used
to reduce the bias in the estimate of ellipticity. we perform numerical tests
for our method, and demonstrate that it can reduce the bias and determine the
halo ellipticity as a function of radius. We also point out that the minimum
mean flexion ratio can be used to trace the centres of galaxy clusters.Comment: 9 pages,9 figures, MNRAS accepte
γ-H2AX foci as in vivo effect biomarker in children emphasize the importance to minimize x-ray doses in paediatric CT imaging
Objectives: Investigation of DNA damage induced by CT x-rays in paediatric patients versus patient dose in a multicentre setting.
Methods: From 51 paediatric patients (median age, 3.8 years) who underwent an abdomen or chest CT examination in one of the five participating radiology departments, blood samples were taken before and shortly after the examination. DNA damage was estimated by scoring gamma-H2AX foci in peripheral blood T lymphocytes. Patient-specific organ and tissue doses were calculated with a validated Monte Carlo program. Individual lifetime attributable risks (LAR) for cancer incidence and mortality were estimated according to the BEIR VII risk models.
Results: Despite the low CT doses, a median increase of 0.13 gamma-H2AX foci/cell was observed. Plotting the induced gamma-H2AX foci versus blood dose indicated a low-dose hypersensitivity, supported also by an in vitro dose-response study. Differences in dose levels between radiology centres were reflected in differences in DNA damage. LAR of cancer mortality for the paediatric chest CT and abdomen CT cohort was 0.08 and 0.13% respectively.
Conclusion: CT x-rays induce DNA damage in paediatric patients even at low doses and the level of DNA damage is reduced by application of more effective CT dose reduction techniques and paediatric protocols
The Malleability of Developmental Trends in Neutral and Negative Memory Illusions
Among many legal professionals and memory researchers there exists the assumption that susceptibility to false memory decreases with age. In four misinformation experiments, we show that under conditions that focus on the meaning of experiences, children are not always the most susceptible to suggestion-induced false memories. We begin by presenting a short overview of previous developmental false memory studies, the majority of which have found that the susceptibility to misinformation decreases with age. In Experiment 1, 6/7-year-olds, 11/12-year-olds, and adults received a video and were confronted with misinformation about related but non-presented details. Older children and adults had higher misinformation acceptance rates than younger children. In Experiment 2, we replicated this finding adding a younger child group (4/6-year-olds). In Experiments 3 and 4, we used new material and again found that susceptibility to misinformation increased with age. Together, these experiments show that children’s memory accuracy is not necessarily inferior to that of adults’
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