329 research outputs found
Dimensional Reduction, Seiberg--Witten Map and Supersymmetry
It is argued that dimensional reduction of Seiberg-Witten map for a gauge
field induces Seiberg-Witten maps for the other noncommutative fields of a
gauge invariant theory. We demonstrate this observation by dimensionally
reducing the noncommutative N=1 SYM theory in 6 dimensions to obtain
noncommutative N=2 SYM in 4 dimensions. We explicitly derive Seiberg-Witten
maps of the component fields in 6 and 4 dimensions. Moreover, we give a general
method to define the deformed supersymmetry transformations that leaves the
actions invariant after performing the Seiberg-Witten maps.Comment: 14 pages. One Ref. added. To appear in PR
On the structure and evolution of planets and their host stars effects of various heating mechanisms on the size of giant gas planets
It is already stated in the previous studies that the radius of the giant
planets is affected by stellar irradiation. The confirmed relation between
radius and incident flux depends on planetary mass intervals. In this study, we
show that there is a single relation between radius and irradiated energy per
gram per second (), for all mass intervals. There is an extra increase in
radius of planets if is higher than 1100 times energy received by the
Earth (). This is likely due to dissociation of molecules. The tidal
interaction as a heating mechanism is also considered and found that its
maximum effect on the inflation of planets is about 15 per cent. We also
compute age and heavy element abundances from the properties of host stars,
given in the TEPCat catalogue (Southworth 2011). The metallicity given in the
literature is as [Fe/H]. However, the most abundant element is oxygen, and
there is a reverse relation between the observed abundances [Fe/H] and [O/Fe].
Therefore, we first compute [O/H] from [Fe/H] by using observed abundances, and
then find heavy element abundance from [O/H]. We also develop a new method for
age determination. Using the ages we find, we analyse variation of both radius
and mass of the planets with respect to time, and estimate the initial mass of
the planets from the relation we derive for the first time. According to our
results, the highly irradiated gas giants lose 5 per cent of their mass in
every 1 Gyr.Comment: 15 pages, 13 figures, 3 tables. Accepted by MNRA
Keeping the breath in mind: Respiration, neural oscillations, and the free energy principle
Scientific interest in the brain and body interactions has been surging in recent years. One fundamental yet underexplored aspect of brain and body interactions is the link between the respiratory and the nervous systems. In this article, we give an overview of the emerging literature on how respiration modulates neural, cognitive and emotional processes. Moreover, we present a perspective linking respiration to the free-energy principle. We frame volitional modulation of the breath as an active inference mechanism in which sensory evidence is recontextualized to alter interoceptive models. We further propose that respiration-entrained gamma oscillations may reflect the propagation of prediction errors from the sensory level up to cortical regions in order to alter higher level predictions. Accordingly, controlled breathing emerges as an easily accessible tool for emotional, cognitive, and physiological regulation
An Embodied Cognition Perspective on the Role of Interoception in the Development of the Minimal Self
Interoception is an often neglected but crucial aspect of the human minimal self. In this perspective, we extend the embodiment account of interoceptive inference to explain the development of the minimal self in humans. To do so, we first provide a comparative overview of the central accounts addressing the link between interoception and the minimal self. Grounding our arguments on the embodiment framework, we propose a bidirectional relationship between motor and interoceptive states, which jointly contribute to the development of the minimal self. We present empirical findings on interoception in development and discuss the role of interoception in the development of the minimal self. Moreover, we make theoretical predictions that can be tested in future experiments. Our goal is to provide a comprehensive view on the mechanisms underlying the minimal self by explaining the role of interoception in the development of the minimal self
Impacts of red pepper supplemented diets and different storage conditions on eggs obtained from free-range laying hens
Egg quality depends on many conditions, including diet and storage temperature. Consumers usually assess it by checking yolk colour. The aim of the study was to indicate the effects of storage periods (7, 14 and 21 days) and temperature (room and refrigerator) on egg quality parameters, especially yolk colour. The experiment was carried out with 150 eggs, which were collected from free-range Lohmann brown laying hens (42 weeks old) fed with or without 0.75% red pepper supplemented diets. The highest weight loss was observed in the eggs stored at room temperature (23 °C, 64% humidity) for 21 days. In addition, it was discovered that the highest air cell height (ACH) was detected in the eggs stored at room temperature for 14 and 21 days. Red pepper supplementation and storage time and temperature were found to have been effective on the Roche yolk colour fan values (RYCF), lightness (L*) and yellowness (b*). Additionally, red pepper supplementation had a significantly positive effect on the redness (a*) value of the yolk. However, no statistical difference in the a* value was determined between the fresh eggs and the stored eggs supplemented with red pepper. The supplementation of 0.75% red pepper as a natural colouring agent to the diets of free-range laying hens had a positive effect on the yolk colour, which is an important attribution for consumer perception. Furthermore, the colours of the yolks of eggs stored in the refrigerator for a week were not significantly different from the fresh ones. Consequently, the present study suggests feeding laying hens diets supplemented with 0.75% red pepper might be useful in improving yolk colour. The results indicate that the eggs stored in the refrigerator might be closer to the characteristics of fresh eggs. In contrast, eggs stored at room temperature showed more deterioration between treatments.Keywords: Colour evaluation methods, egg quality, free-range, yolk colou
An embodied cognition perspective on the role of interoception in the development of the minimal self
Interoception is an often neglected but crucial aspect of the human minimal self. In this perspective, we extend the embodiment account of interoceptive inference to explain the development of the minimal self in humans. To do so, we first provide a comparative overview of the central accounts addressing the link between interoception and the minimal self. Grounding our arguments on the embodiment framework, we propose a bidirectional relationship between motor and interoceptive states, which jointly contribute to the development of the minimal self. We present empirical findings on interoception in development and discuss the role of interoception in the development of the minimal self. Moreover, we make theoretical predictions that can be tested in future experiments. Our goal is to provide a comprehensive view on the mechanisms underlying the minimal self by explaining the role of interoception in the development of the minimal self
Effects of reinforcement learning on gaze following of gaze and head direction in early infancy: An interactive eye‐tracking study
The current four experiments investigated gaze following behavior in response to gaze and head turns in 4‐month‐olds and how reinforcement learning influences this behavior (N = 99). Using interactive eye tracking, infants’ gaze elicited an animation whenever infants followed a person’s head or gaze orientation (Experiment 1.1, 2.1 and 2.2) or looked at the opposite side (Experiment 1.2). Infants spontaneously followed the direction of a turning head with and without simultaneously shifted gaze direction (Cohen’s d: 0.93–1.05) but not the direction of isolated gaze shifts. We only found a weak effect of reinforcement on gaze following in one of the four experiments. Results will be discussed with regard to the impact of reinforcement on the maintenance of already existing gaze following behavior
An experimental investigation of chatter effects on tool life
Tool wear is one of the most important considerations in machining operations as it affects surface quality and integrity, productivity and cost. The most commonly used model for tool life analysis is the one proposed by F.W. Taylor about a century ago. Although the extended form of this equation includes the effects of important cutting conditions on tool wear, tool life studies are mostly performed under stable cutting conditions where the effect of chatter vibrations are not considered. This paper presents an empirical attempt to understand tool life under vibratory cutting conditions. Tool wear data are collected in turning and milling on different work materials under stable and chatter conditions. The effects of cutting conditions as well as severity of chatter on tool life are analyzed. The results indicate significant reduction in tool life due to chatter as expected. They also show that the severity of chatter, and thus the vibration amplitude, strongly reduces the life of cutting tools. These results can be useful in evaluating the real cost of chatter by including the reduced tool life. They can also be useful in justifying the cost of chatter suppression and more rigid machining systems
The Black Hole in the Compact, High-dispersion Galaxy NGC 1271
Located in the Perseus cluster, NGC 1271 is an early-type galaxy with a small
effective radius of 2.2 kpc and a large stellar velocity dispersion of 276 km/s
for its K-band luminosity of 8.9x10^{10} L_sun. We present a mass measurement
for the black hole in this compact, high-dispersion galaxy using observations
from the integral field spectrograph NIFS on the Gemini North telescope
assisted by laser guide star adaptive optics, large-scale integral field unit
observations with PPAK at the Calar Alto Observatory, and Hubble Space
Telescope WFC3 imaging observations. We are able to map out the stellar
kinematics on small spatial scales, within the black hole sphere of influence,
and on large scales that extend out to four times the galaxy's effective
radius. We find that the galaxy is rapidly rotating and exhibits a sharp rise
in the velocity dispersion. Through the use of orbit-based stellar dynamical
models, we determine that the black hole has a mass of (3.0^{+1.0}_{-1.1}) x
10^9 M_sun and the H-band stellar mass-to-light ratio is 1.40^{+0.13}_{-0.11}
M_sun/L_sun (1-sigma uncertainties). NGC 1271 occupies the sparsely-populated
upper end of the black hole mass distribution, but is very different from the
Brightest Cluster Galaxies (BCGs) and giant elliptical galaxies that are
expected to host the most massive black holes. Interestingly, the black hole
mass is an order of magnitude larger than expectations based on the galaxy's
bulge luminosity, but is consistent with the mass predicted using the galaxy's
bulge stellar velocity dispersion. More compact, high-dispersion galaxies need
to be studied using high spatial resolution observations to securely determine
black hole masses, as there could be systematic differences in the black hole
scaling relations between these types of galaxies and the BCGs/giant
ellipticals, thereby implying different pathways for black hole and galaxy
growth.Comment: accepted for publication in Ap
- …