3,025 research outputs found
Recursive Compressed Sensing
We introduce a recursive algorithm for performing compressed sensing on
streaming data. The approach consists of a) recursive encoding, where we sample
the input stream via overlapping windowing and make use of the previous
measurement in obtaining the next one, and b) recursive decoding, where the
signal estimate from the previous window is utilized in order to achieve faster
convergence in an iterative optimization scheme applied to decode the new one.
To remove estimation bias, a two-step estimation procedure is proposed
comprising support set detection and signal amplitude estimation. Estimation
accuracy is enhanced by a non-linear voting method and averaging estimates over
multiple windows. We analyze the computational complexity and estimation error,
and show that the normalized error variance asymptotically goes to zero for
sublinear sparsity. Our simulation results show speed up of an order of
magnitude over traditional CS, while obtaining significantly lower
reconstruction error under mild conditions on the signal magnitudes and the
noise level.Comment: Submitted to IEEE Transactions on Information Theor
Fundamental properties of solar-like oscillating stars from frequencies of minimum : II. Model computations for different chemical compositions and mass
The large separations between the oscillation frequencies of solar-like stars
are measures of stellar mean density. The separations have been thought to be
mostly constant in the observed range of frequencies. However, detailed
investigation shows that they are not constant, and their variations are not
random but have very strong diagnostic potential for our understanding of
stellar structure and evolution. In this regard, frequencies of the minimum
large separation are very useful tools. From these frequencies, in addition to
the large separation and frequency of maximum amplitude, Y\i ld\i z et al.
recently have developed new methods to find almost all the fundamental stellar
properties. In the present study, we aim to find metallicity and helium
abundances from the frequencies, and generalize the relations given by Y\i ld\i
z et al. for a wider stellar mass range and arbitrary metallicity () and
helium abundance (). We show that the effect of metallicity is {
significant} for most of the fundamental parameters. For stellar mass, for
example, the expression must be multiplied by (Z/Z_{\sun})^{0.12}. For
arbitrary helium abundance, M \propto (Y/Y_{\sun})^{0.25} . Methods for
determination of and from pure asteroseismic quantities are based on
amplitudes (differences between maximum and minimum values of \Dnu) in the
oscillatory component in the spacing of oscillation frequencies. Additionally,
we demonstrate that the difference between the first maximum and the second
minimum is very sensitive to . It also depends on and small separation between the frequencies. Such a dependence leads us
to develop a method to find (and ) from oscillation frequencies. The
maximum difference between the estimated and model values is about 14 per
cent. It is 10 per cent for .Comment: 8 pages, 13 figures; published in MNRAS (2015
Comparison of Gaia and asteroseismic distances
Asteroseismology provides fundamental properties (mass, radius and effective
temperature) of solar-like oscillating stars using so-called scaling relations.
These properties allow the computation of the asteroseismic distance of stars.
We compare the asteroseismic distances with the recently released Gaia
distances for 74 stars studied in Y{\i}ld{\i}z et al. There is a very good
agreement between these two distances; for 64 of these stars, the difference is
less than 10 per cent. However, a systematic difference is seen if we use the
effective temperature obtained by spectroscopic methods; the Gaia distances are
about 5 per cent greater than the asteroseismic distances.Comment: 4 pages, 4 figures, accepted by MNRA
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
YOGURT; A NOVEL EXCIPIENT (WITH ITS LYSED BACTERIA, AMINO ACIDS, VITAMINS, FATTY ACIDS, AND MINERALS) FOR “TOPICAL DERMATOLOGICAL PRODUCTS” AND FOR “SKIN MICROBIOTA”
In recent years various Microbiomes (Skin, Gut Lumen) of the human body have attracted the attention of different research groups. In the meantime it has been shown that the conventional therapy of different diseases by making use of antibiotics and similar antibacterial treatments may disturb the harmony of the Skin Microbiome, resulting in dysbiosis. There are efforts of using “live” or “tyndallized (lysed)” probiotics in order to treat different diseases of the skin. It is also known that amino acids are one of the important key elements of the skin. In this paper, a hypothesis for the utilization of yogurt as an excipient for various topical dermatological products will be proposed. Yogurt contains significant amounts of; Probiotics (starter cultures), Amino Acids, Vitamins, Minerals and various Fatty Acids (saturated, monounsaturated and polyunsaturated). Besides, it has been shown that Antimicrobial Peptides (Bacteriocins) are also present in yogurt. Yogurt could eventually be used as an excipient for the production of various topical dermatological products in order to deliver some of the above-mentioned constituents to the Stratum Corneum (Skin) locally
An anatomical study on the three-headed biceps brachii in human foetuses, and clinical relevance
The biceps brachii (BB) is as one of the most variable muscles in the human body
in terms of number and morphology of its heads. The most frequent variation is
the presence of a third head, which has been reported by several authors in
different populations. Our aim was to find the occurrence of the supernumerary
head of BB in Turkish foetuses. Out of the 24 upper limbs of the foetuses, two
(8.33%) arms were found to have a three-headed BB. The variations were present
unilaterally in the right arm of one male foetus and one female foetus. In one of
the cases, the third head of BB originated from the anteromedial aspect of the
humerus just distal to the insertion of the coracobrachilais, medial to the brachialis,
and in the other the third head was a thin muscle bundle, which arose on
the lateral side of the insertion of coracobrachialis and over the origin of the
brachialis. Both of them were extended distally and joined the common tendon.
The occasional presence of the three-headed BB in the foetuses observed in the
present study was similar to those of adults reported in previous studies. In conclusion,
these variations are not rare and are interesting not only to anatomists
but also to orthopaedic surgeons, plastic surgeons, traumatologists, physiotherapists,
doctors dealing with sports medicine, and radiologists. (Folia Morphol 2011;
70, 2: 116–120
What can generic neural networks learn from a child's visual experience?
Young children develop sophisticated internal models of the world based on
their egocentric visual experience. How much of this is driven by innate
constraints and how much is driven by their experience? To investigate these
questions, we train state-of-the-art neural networks on a realistic proxy of a
child's visual experience without any explicit supervision or domain-specific
inductive biases. Specifically, we train both embedding models and generative
models on 200 hours of headcam video from a single child collected over two
years. We train a total of 72 different models, exploring a range of model
architectures and self-supervised learning algorithms, and comprehensively
evaluate their performance in downstream tasks. The best embedding models
perform at 70% of a highly performant ImageNet-trained model on average. They
also learn broad semantic categories without any labeled examples and learn to
localize semantic categories in an image without any location supervision.
However, these models are less object-centric and more background-sensitive
than comparable ImageNet-trained models. Generative models trained with the
same data successfully extrapolate simple properties of partially masked
objects, such as their texture, color, orientation, and rough outline, but
struggle with finer object details. We replicate our experiments with two other
children and find very similar results. Broadly useful high-level visual
representations are thus robustly learnable from a representative sample of a
child's visual experience without strong inductive biases.Comment: 26 pages, 14 figures, 3 tables; code & all pretrained models
available from https://github.com/eminorhan/silicon-menageri
Anatomical characteristics of the lingual foramen in ancient skulls: a cone beam computed tomography study in an Anatolian population
Background: The purpose of this study is to evaluate the anatomical features of lingual foramina and their bony canals in Anatolian ancient mandibles (9–10th century) by using cone beam computed tomography (CBCT). Materials and methods: Fifty-eight ancient dry mandibles were scanned with CBCT. Lingual foramina were grouped into midline, paramedian, posterior foramina and combination of these groups. Midline group was also classified according to internal surface of the mandible (gonial tubercles [GTs]). The incidence, vertical distance and diameter of lingual foramina were measured according to age groups and gender. Results: The incidence of the lingual foramen was 96.6%. Midline of the symphysis had the highest incidence (34.4%) of foramina (p < 0.05), followed by both midline and paramedian type (32.8%; p < 0.05). Classification in terms of GT represented class 3 as the most encountered group (28.6%). Number of foramina observed in the mandibles ranged from 0 to 6 with the incidence of 3.4% and 32.8%, respectively. The male and < 35 years groups presented larger measurement values in midline region (p < 0.05). Conclusions: Mandibular lingual foramina and bony canals are frequently present in ancient mandibles. When compared with modern subjects, similar findings are observed according to published literatures. CBCT is also proved to be an effective imaging modality in the detection of lingual foramina and canals in anthropological studies
- …