9,051 research outputs found
Affective visuomotor interaction: a functional model for socially competent robot grasping
In the context of human-robot social interactions, the ability of interpreting the emotional value of objects and actions is critical if we wish robots to achieve truly meaningful interchanges with human partners. We review here the most significant findings related to reward management and values assignment in the primate brain, with particular regard to the prefrontal cortex. Based on such findings, we propose a novel model of vision-based grasping in which the context-dependent emotional value of available options (e.g. damageable or dangerous items) is taken into account when interacting with objects in the real world. The model is both biologically plausible and suitable for being applied to a robotic setup. We provide a testing framework along with implementation guidelines
Effectiveness of a commercial lure to attract red fox
In camera trap studies, attractants may be used to increase detection probabilities of wildlife, which may help to improve estimates of abundance and occupancy. Using a semi-experimental approach, we investigated if a commercial, strawberry scented lure increased detection probability and visiting time duration in red fox Vulpes vulpes, and the potential reasons for variation in these parameters. In September 2020, within the Stelvio National Park, central Italian Alps, 32 camera sites were randomly assigned to 4 different treatments: 8 to commercial lure, the target of our investigation; 8 to orange aroma, to test for the "curiosity" effect; 8 to cat kibble, to test for the "likability" effect; 8 to camera trap only, the control test. Detection probability and duration of visiting time were estimated using hurdle negative binomial regression models. Daily detection probability was significantly higher with lure (0.078), orange aroma (0.086), kibble (0.075) than with camera trap only (0.031); in the first day after treatment, the time an animal spent in front of the cameras significantly increased with orange aroma (16.61 s) and kibble (33.78 s) compared to lure (9.97 s) and camera trap only (0.38 s). Our results support the use of lures to improve detection probability and visit duration in red fox, but we could not disentangle the drivers of increased parameter estimates. When consumable costs are considered, the use of the commercial strawberry scented lure does not appear justified for both detection probability and visit duration, and cheaper alternatives may be preferable
Sonic hedgehog medulloblastoma cancer stem cells mirnome and transcriptome highlight novel functional networks
Molecular classification has improved the knowledge of medulloblastoma (MB), the most common malignant brain tumour in children, however current treatments cause severe side effects in patients. Cancer stem cells (CSCs) have been described in MB and represent a sub population characterised by self-renewal and the ability to generate tumour cells, thus representing the reservoir of the tumour. To investigate molecular pathways that characterise this sub population, we isolated CSCs from Sonic Hedgehog Medulloblastoma (SHH MB) arisen in Patched 1 (Ptch1) heterozygous mice, and performed miRNA-and mRNA-sequencing. Comparison of the miRNA-sequencing of SHH MB CSCs with that obtained from cerebellar Neural Stem Cells (NSCs), allowed us to obtain a SHH MB CSC miRNA differential signature. Pathway enrichment analysis in SHH MB CSCs mirnome and transcriptome was performed and revealed a series of enriched pathways. We focused on the putative targets of the SHH MB CSC miRNAs that were involved in the enriched pathways of interest, namely pathways in cancer, PI3k-Akt pathway and protein processing in endoplasmic reticulum pathway. In silico analysis was performed in SHH MB patients and identified several genes, whose expression was associated with worse overall survival of SHH MB patients. This study provides novel candidates whose functional role should be further investigated in SHH MB
Nucleotide Sequence of the Streptococcin A-FF22 Lantibiotic Regulon: Model for Production of the Lantibiotic SA-FF22 by Strains of Streptococcus pyogenes
Streptococcin A-FF22 (SA-FF22) is a type AII linear lantibiotic produced by Streptococcus pyogenes strain FF22. Sequence analysis of an approximate 10 kb region of DNA showed it to contain nine open reading frames arranged in three operons responsible for regulation, biosynthesis and immunity of SA-FF22. This region is organized similarly to the Lactococcus lactis lacticin 481 region, however, unlike lacticin 481, a two-component regulatory system is essential for SA-FF22 production. located immediately downstream of the scn region is a putative transposase gene, the presence of which supports earlier data that indicated a mobile nature to this region. (©) 1999 Published by Elsevier Science B.V. All rights reserved
A Study of Holographic Renormalization Group Flows in d=6 and d=3
We present an explicit study of the holographic renormalization group (RG) in
six dimensions using minimal gauged supergravity. By perturbing the theory with
the addition of a relevant operator of dimension four one flows to a
non-supersymmetric conformal fixed point. There are also solutions describing
non-conformal vacua of the same theory obtained by giving an expectation value
to the operator. One such vacuum is supersymmetric and is obtained by using the
true superpotential of the theory. We discuss the physical acceptability of
these vacua by applying the criteria recently given by Gubser for the four
dimensional case and find that those criteria give a clear physical picture in
the six dimensional case as well. We use this example to comment on the role of
the Hamilton-Jacobi equations in implementing the RG. We conclude with some
remarks on AdS_4 and the status of three dimensional superconformal theories
from squashed solutions of M-theory.Comment: 15 pages, 5 figures, V2: minor change
Putting cells in motion: Advantages of endogenous boosting of BDNF production
Motor exercise, such as sport or musical activities, helps with a plethora of diseases by modulating brain functions in neocortical and subcortical regions, resulting in behavioural changes related to mood regulation, well-being, memory, and even cognitive preservation in aging and neurodegenerative diseases. Although evidence is accumulating on the systemic neural mechanisms mediating these brain effects, the specific mechanisms by which exercise acts upon the cellular level are still under investigation. This is particularly the case for music training, a much less studied instance of motor exercise than sport. With regards to sport, consistent neurobiological research has focused on the brain-derived neurotrophic factor (BDNF), an essential player in the central nervous system. BDNF stimulates the growth and differentiation of neurons and synapses. It thrives in the hippocampus, the cortex, and the basal forebrain, which are the areas vital for memory, learning, and higher cognitive functions. Animal models and neurocognitive experiments on human athletes converge in demonstrating that physical exercise reliably boosts BDNF levels. In this review, we highlight comparable early findings obtained with animal models and elderly humans exposed to musical stimulation, showing how perceptual exposure to music might affect BDNF release, similar to what has been observed for sport. We subsequently propose a novel hypothesis that relates the neuroplastic changes in the human brains after musical training to genetically-and exercise-driven BDNF levels
Probing gas and dust in the tidal tail of NGC 5221 with the type Ia supernova iPTF16abc
Context. Type Ia supernovae (SNe Ia) can be used to address numerous
questions in astrophysics and cosmology. Due to their well known spectral and
photometric properties, SNe Ia are well suited to study gas and dust along the
lines-of-sight to the explosions. For example, narrow Na I D and Ca II H&K
absorption lines can be studied easily, because of the well-defined spectral
continuum of SNe Ia around these features. Aims. We study the gas and dust
along the line-of-sight to iPTF16abc, which occurred in an unusual location, in
a tidal arm, 80 kpc from centre of the galaxy NGC 5221. Methods. Using a
time-series of high-resolution spectra, we examine narrow Na I D and Ca II H&K
absorption features for variations in time, which would be indicative for
circumstellar (CS) matter. Furthermore, we take advantage of the well known
photometric properties of SNe Ia to determine reddening due to dust along the
line-of-sight. Results. From the lack of variations in Na I D and Ca II H&K, we
determine that none of the detected absorption features originate from the CS
medium of iPTF16abc. While the Na I D and Ca II H&K absorption is found to be
optically thick, a negligible amount of reddening points to a small column of
interstellar dust. Conclusions. We find that the gas along the line-of-sight to
iPTF16abc is typical of what might be found in the interstellar medium (ISM)
within a galaxy. It suggests that we are observing gas that has been tidally
stripped during an interaction of NGC 5221 with one of its neighbouring
galaxies in the past years. In the future, the gas clouds could
become the locations of star formation. On a longer time scale, the clouds
might diffuse, enriching the circum-galactic medium (CGM) with metals. The gas
profile along the line-of-sight should be useful for future studies of the
dynamics of the galaxy group containing NGC 5221.Comment: 8 pages, 6 figure
Yang-Mills theory from non-critical string
The correspondence of the non-critical string theory and the Yang-Mills
theory is examined according to the recent Polyakov's proposal, and two
possible solutions of the bulk equations are addressed near the fixed points of
the pure Yang-Mills theory: (i) One solution asymptotically approaches to the
AdS space at the ultraviolet limit where the conformally invariant field theory
is realized. (ii) The second one approaches to the flat space in both the
infrared and the ultraviolet limits. The area law of the Wilson-loop and the
asymptotic freedom with logarithmic behaviour are seen in the respective limit.Comment: 17 pages, no figure, Late
Beta-functions in Yang-Mills Theory from Non-critical String
The renormalization group equations of the Yang-Mills theory are examined in
the non-critical string theory according to the framework of the holography.
Under a simple ansatz for the tachyon, we could find several interesting
solutions which are classified by the value of the tachyon potential at the
vacuum. We show two typical, asymptotic-free solutions which are different in
their infrared behaviors. For both types of solutions, we could obtain
quark-confinement potential from the Wilson-loop. The stability of the tachyon
and the ZigZag symmetry are also discussed for these solutions.Comment: 16 pages, 5 figure
Identification of Flavescence dorée-related phytoplasma infecting grapevines on the isle of Ischia (southern Italy)
Among the grapevine diseases, Flavescence dorée (FD) is considered to be one of the greatest threats for grapevine cultivation throughout Europe. In Italy, where several major outbreaks of FD have occurred in the past, the disease is still mainly restricted to the northern regions and is under mandatory regulation. In 2011 the disease was recorded for the first time in southern Italy, in several vineyards located on the isle of Ischia (Campania). In order to determine the FD-related phytoplasma infecting these grapevines, molecular investigations were carried out on grapevine samples collected from several FD infected vineyards. The 16S rDNA/spacer region and the FD9 non-ribosomal fragment (secY gene) were investigated using a PCR/RFLP based method; a nucleotide sequence analysis of the FD9 amplified fragments was also carried out. The RFLP profiles obtained from all the analyzed samples showed the presence of FD-D phytoplasma type, on both 16S and secY genomic regions. Sequencing of the FD9 fragments showed a 99 % nucleotide sequence identity among the tested isolates and the various FD-D strains retrieved from the NCBI database.
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