345 research outputs found
From Antenna to Antenna: Lateral Shift of Olfactory Memory Recall by Honeybees
Honeybees, Apis mellifera, readily learn to associate odours with sugar rewards and we show here that recall of the olfactory memory, as demonstrated by the bee extending its proboscis when presented with the trained odour, involves first the right and then the left antenna. At 1–2 hour after training using both antennae, recall is possible mainly when the bee uses its right antenna but by 6 hours after training a lateral shift has occurred and the memory can now be recalled mainly when the left antenna is in use. Long-term memory one day after training is also accessed mainly via the left antenna. This time-dependent shift from right to left antenna is also seen as side biases in responding to odour presented to the bee's left or right side. Hence, not only are the cellular events of memory formation similar in bees and vertebrate species but also the lateralized networks involved may be similar. These findings therefore seem to call for remarkable parallel evolution and suggest that the proper functioning of memory formation in a bilateral animal, either vertebrate or invertebrate, requires lateralization of processing
Thorough analysis of input physics in CESAM and CLES codes
This contribution is not about the quality of the agreement between stellar
models computed by CESAM and CLES codes, but more interesting, on what
ESTA-Task~1 run has taught us about these codes and about the input physics
they use. We also quantify the effects of different implementations of the same
physics on the seismic properties of the stellar models, that in fact is the
main aim of ESTA experiments.Comment: 11 pages, 12 fig. Accepted for publication in ApSS CoRoT/ESTA Volu
The 21Na(p,gamma)22Mg Reaction and Oxygen-Neon Novae
The 21Na(p,gamma)22Mg reaction is expected to play an important role in the
nucleosynthesis of 22Na in Oxygen-Neon novae. The decay of 22Na leads to the
emission of a characteristic 1.275 MeV gamma-ray line. This report provides the
first direct measurement of the rate of this reaction using a radioactive 21Na
beam, and discusses its astrophysical implications. The energy of the important
state was measured to be E= 205.7 0.5 keV with a resonance
strength meV.Comment: Accepted for publication in Physical Review Letter
Positive emotions: passionate scholarship and student transformation
This paper challenges the practical and conceptual understanding of the role of emotions in higher education from the twin perspectives of transition and transformation. Focusing on the neglected area of positive emotions, exploratory data reveal a rich, low-level milieu of undergraduate emotional awareness in students chiefly attributed to pedagogic actions, primarily extrinsically orientated, and pervasive throughout the learning experience. The data conceive positive affect as oppositional, principally ephemeral and linked to performative pedagogic endeavours of getting, knowing and doing. A cyclical social dynamic of reciprocity, generating positive feedback loops, is highlighted. Finally we inductively construct a tentative 'emotion-transition framework' to assist our understanding of positive emotion as a force for transformational change; our contention is that higher education might proactively craft pedagogic spaces so as to unite the feeling discourse, the thinking discourse (epistemological self) and the wider life-self (ontological) discourse
The effect of 12C + 12C rate uncertainties on the evolution and nucleosynthesis of massive stars
[Shortened] The 12C + 12C fusion reaction has been the subject of
considerable experimental efforts to constrain uncertainties at temperatures
relevant for stellar nucleosynthesis. In order to investigate the effect of an
enhanced carbon burning rate on massive star structure and nucleosynthesis, new
stellar evolution models and their yields are presented exploring the impact of
three different 12C + 12C reaction rates. Non-rotating stellar models were
generated using the Geneva Stellar Evolution Code and were later post-processed
with the NuGrid Multi-zone Post-Processing Network tool. The enhanced rate
causes core carbon burning to be ignited more promptly and at lower
temperature. This reduces the neutrino losses, which increases the core carbon
burning lifetime. An increased carbon burning rate also increases the upper
initial mass limit for which a star exhibits a convective carbon core. Carbon
shell burning is also affected, with fewer convective-shell episodes and
convection zones that tend to be larger in mass. Consequently, the chance of an
overlap between the ashes of carbon core burning and the following carbon shell
convection zones is increased, which can cause a portion of the ashes of carbon
core burning to be included in the carbon shell. Therefore, during the
supernova explosion, the ejecta will be enriched by s-process nuclides
synthesized from the carbon core s process. The yields were used to estimate
the weak s-process component in order to compare with the solar system
abundance distribution. The enhanced rate models were found to produce a
significant proportion of Kr, Sr, Y, Zr, Mo, Ru, Pd and Cd in the weak
component, which is primarily the signature of the carbon-core s process.
Consequently, it is shown that the production of isotopes in the Kr-Sr region
can be used to constrain the 12C + 12C rate using the current branching ratio
for a- and p-exit channels.Comment: The paper contains 17 figures and 7 tables. Table 7 will be published
in full online onl
Daily amplitudes of air temperature in Zagreb, Croatia
U svim mjesecima aperiodička amplituda je veća od periodičke. Amplitude su veće na periferiji nego u centru grada. Amplitude su manje na većoj nadmorskoj visini. U razdoblju 1953.-1983. aperiodička amplituda je u godišnjem prosjeku pala u Podsusedu za 0,3˚, a na Griču za 0,6˚. Aperiodička amplituda u studenom je u Podsusedu porasla za 2,1˚, a na Griču za 0,8˚. Srpanjska aperiodička amplituda u Podsusedu porasla je za 0,2˚, a na Griču za 0,4˚.In all months aperiodic amplitude is greater than periodic one. The amplitudes are much greateron the periphery than in the central area. The amplitudes are smaller on the higher altitude. In the period 1953-1983 one reveals that annual aperiodic daily amplitude in Podsused are 0,3˚, and in Grič 0,6˚ lower than at the beginning of the period. In November the aperiodic amplitude is 2,1˚ greater, and in Grič only 0,8˚ greater than at the beginning of analysed period. The mean July aperiodic amplitude in Podsused is 0,2˚ greater, and 0,4˚ greater in Gričthan at the beginning of the analysed period
Recent Advances in Modeling Stellar Interiors
Advances in stellar interior modeling are being driven by new data from
large-scale surveys and high-precision photometric and spectroscopic
observations. Here we focus on single stars in normal evolutionary phases; we
will not discuss the many advances in modeling star formation, interacting
binaries, supernovae, or neutron stars. We review briefly: 1) updates to input
physics of stellar models; 2) progress in two and three-dimensional evolution
and hydrodynamic models; 3) insights from oscillation data used to infer
stellar interior structure and validate model predictions (asteroseismology).
We close by highlighting a few outstanding problems, e.g., the driving
mechanisms for hybrid gamma Dor/delta Sct star pulsations, the cause of giant
eruptions seen in luminous blue variables such as eta Car and P Cyg, and the
solar abundance problem.Comment: Proceedings for invited talk at conference High Energy Density
Laboratory Astrophysics 2010, Caltech, March 2010, submitted for special
issue of Astrophysics and Space Science; 7 pages; 5 figure
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Biophysical Effects and Ground Force of the Baldree Traffic Simulator
Traffic simulators are often utilized when researching turfgrass wear tolerance and recovery. However, the availability of a durable traffic simulator capable of producing dynamic force is limited. Therefore, the objectives of this research were to: 1) evaluate a novel traffic simulator with improved durability and capable of producing dynamic force and 2) evaluate the bio-physical effects of the traffic simulator on a native soil turfgrass system. The Baldree Traffic Simulator is a modified Ryan GA 30 riding aerification unit, equipped with fabricated, spring loaded steel plate feet studded with screw in cleats. The effects of this unit on a ‘Tifway’ bermudagrass (Cynodon dactylon [L.] Pers. × C. transvaalensis Burtt-Davy) system established on a Tifton loamy sand (Fine-loamy, kaolinitic, thermic Plinthic Kandiudults) were evaluated at the Coastal Plains Experiment Station, Tifton, GA. Factors included location (1 and 2) and traffic rate (0, 12 and 24 passes applied over a 6 week period). Field data included soil bulk density, turf density, and percent green turf cover. An in-ground force plate at the McPhail Equine Performance Center, East Lansing, MI was used to quantify vertical and net shear ground reaction force produced by the Baldree traffic simulator when operated in the forward and backward direction. The Baldree traffic simulator produced more cleat marks per pass than the Brinkman and Cady traffic simulators, as well as vertical force values comparable to that of a trotting horse. At the low traffic rate the Baldree traffic simulator increased soil bulk density, while turf density, percent green turf cover and vegetative indices decreased, therefore, the tool can be used to simulate heavy traffic conditions with a minimum number of passes.This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Crop Science Society of America and can be found at: https://www.crops.org/publications/cs
Professional excellence: the necessary convergence of psychological variables
O estudo da excelência humana assume essencialmente dois enfoques, um deles acentuando as variáveis psicológicas dos indivíduos e outro enfatizando as aquisições decorrentes da prática ou treino deliberado. Neste artigo procurou-se integrar tais estudos, propondo que o surgimento e a manutenção da excelência pressupõem uma constelação de variáveis psicológicas que vão para além da alta capacidade intelectual. Mais concretamente, descreveu-se um conjunto de variáveis cognitivas, motivacionais e de personalidade, assumidas como relevantes na excelência profissional em diferentes áreas de desempenho e de conhecimento. No seio das variáveis cognitivas e, fazendo uma ponte com as variáveis de personalidade, destaca-se o papel da criatividade para a excelência, reconhecendo a sua particular relevância em algumas áreas de realização profissional.The study of human excellence can be described based on two main approaches focusing either on individuals' psychological variables or on acquisitions by training or deliberate practice. The purpose of this study is to integrate these models based on the assumption that the emergence and maintenance of excellence requires a constellation of fundamental psychological variables that transcend intellectual capacity. More specifically, a set of cognitive, motivational, and personality variables that are considered important for professional excellence in different levels of performance and areas of knowledge were described. Among the cognitive variables and their association with personality variables, it is worth mentioning the significant role of creativity in the pursuit of excellence, recognizing its relevance to specific areas of professional performance.(undefined
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