936 research outputs found
Towards Benchmarking Scene Background Initialization
Given a set of images of a scene taken at different times, the availability
of an initial background model that describes the scene without foreground
objects is the prerequisite for a wide range of applications, ranging from
video surveillance to computational photography. Even though several methods
have been proposed for scene background initialization, the lack of a common
groundtruthed dataset and of a common set of metrics makes it difficult to
compare their performance. To move first steps towards an easy and fair
comparison of these methods, we assembled a dataset of sequences frequently
adopted for background initialization, selected or created ground truths for
quantitative evaluation through a selected suite of metrics, and compared
results obtained by some existing methods, making all the material publicly
available.Comment: 6 pages, SBI dataset, SBMI2015 Worksho
Characterization of a disease-associated mutation affecting a putative splicing regulatory element in intron 6b of the cystic fibrosis transmembrane conductance regulator (CFTR) gene
Cystic fibrosis (CF) is a common recessive disorder caused by >1600 mutations in the CF transmembrane conductance regulator (CFTR) gene. About 13% of CFTR mutations are classified as âsplicing mutations,â but for almost 40% of these, their role in affecting the pre-mRNA splicing of the gene is not yet defined. In this work, we describe a new splicing mutation detected in three unrelated Italian CF patients. By DNA analyses and mRNA studies, we identified the c.1002â1110_1113delTAAG mutation localized in intron 6b of the CFTR gene. At the mRNA level, this mutation creates an aberrant inclusion of a sequence of 101 nucleotides between exons 6b and 7. This sequence corresponds to a portion of intron 6b and resembles a cryptic exon because it is characterized by an upstream ag and a downstream gt sequence, which are most probably recognized as 5âČ- and 3âČ-splice sites by the spliceosome. Through functional analysis of this splicing defect, we show that this mutation abolishes the interaction of the splicing regulatory protein heterogeneous nuclear ribonucleoprotein A2/B1 with an intronic splicing regulatory element and creates a new recognition motif for the SRp75 splicing factor, causing activation of the cryptic exon. Our results show that the c.1002â1110_1113delTAAG mutation creates a new intronic splicing regulatory element in intron 6b of the CFTR gene exclusively recognized by SRp75
Metabolic response of Geobacter sulfurreducens towards electron donor/acceptor variation
Background Geobacter sulfurreducens is capable of coupling the complete oxidation of organic compounds to iron reduction. The metabolic response of G. sulfurreducens towards variations in electron donors (acetate, hydrogen) and acceptors (Fe(III), fumarate) was investigated via 13C-based metabolic flux analysis. We examined the 13C-labeling patterns of proteinogenic amino acids obtained from G. sulfurreducens cultured with 13C-acetate. Results Using 13C-based metabolic flux analysis, we observed that donor and acceptor variations gave rise to differences in gluconeogenetic initiation, tricarboxylic acid cycle activity, and amino acid biosynthesis pathways. Culturing G. sulfurreducens cells with Fe(III) as the electron acceptor and acetate as the electron donor resulted in pyruvate as the primary carbon source for gluconeogenesis. When fumarate was provided as the electron acceptor and acetate as the electron donor, the flux analysis suggested that fumarate served as both an electron acceptor and, in conjunction with acetate, a carbon source. Growth on fumarate and acetate resulted in the initiation of gluconeogenesis by phosphoenolpyruvate carboxykinase and a slightly elevated flux through the oxidative tricarboxylic acid cycle as compared to growth with Fe(III) as the electron acceptor. In addition, the direction of net flux between acetyl-CoA and pyruvate was reversed during growth on fumarate relative to Fe(III), while growth in the presence of Fe(III) and acetate which provided hydrogen as an electron donor, resulted in decreased flux through the tricarboxylic acid cycle. Conclusions We gained detailed insight into the metabolism of G. sulfurreducens cells under various electron donor/acceptor conditions using 13C-based metabolic flux analysis. Our results can be used for the development of G. sulfurreducens as a chassis for a variety of applications including bioremediation and renewable biofuel production
A 1.1 to 1.9 GHz SETI Survey of the Kepler Field: I. A Search for Narrow-band Emission from Select Targets
We present a targeted search for narrow-band (< 5 Hz) drifting sinusoidal
radio emission from 86 stars in the Kepler field hosting confirmed or candidate
exoplanets. Radio emission less than 5 Hz in spectral extent is currently known
to only arise from artificial sources. The stars searched were chosen based on
the properties of their putative exoplanets, including stars hosting candidates
with 380 K > T_eq > 230 K, stars with 5 or more detected candidates or stars
with a super-Earth (R_p 50 day orbit. Baseband voltage data
across the entire band between 1.1 and 1.9 GHz were recorded at the Robert C.
Byrd Green Bank Telescope between Feb--Apr 2011 and subsequently searched
offline. No signals of extraterrestrial origin were found. We estimate that
fewer than ~1% of transiting exoplanet systems host technological civilizations
that are radio loud in narrow-band emission between 1-2 GHz at an equivalent
isotropically radiated power (EIRP) of ~1.5 x 10^21 erg s^-1, approximately
eight times the peak EIRP of the Arecibo Planetary Radar, and we limit the the
number of 1-2 GHz narrow-band-radio-loud Kardashev type II civilizations in the
Milky Way to be < 10^-6 M_solar^-1. Here we describe our observations, data
reduction procedures and results.Comment: Accepted to the Astrophysical Journa
Coulomb and nuclear breakup effects in the single neutron removal reaction 197Au(17C,16C gamma)X
We analyze the recently obtained new data on the partial cross sections and
parallel momentum distributions for transitions to ground as well as excited
states of the 16C core, in the one-neutron removal reaction 197Au(17C,16C
gamma)X at the beam energy of 61 MeV/nucleon. The Coulomb and nuclear breakup
components of the one-neutron removal cross sections have been calculated
within a finite range distorted wave Born approximation theory and an eikonal
model, respectively. The nuclear contributions dominate the partial cross
sections for the core excited states. By adding the nuclear and Coulomb cross
sections together, a reasonable agreement is obtained with the data for these
states. The shapes of the experimental parallel momentum distributions of the
core states are described well by the theory.Comment: Revtex format, two figures included, to appear in Phys. Rev. C.
(Rapid communications
One-neutron knockout from Ni
The single-particle structure of Ni and level structure of Ni
were investigated with the \mbox{Be (Ni,Ni+)} reaction at 73 MeV/nucleon. An inclusive cross
section of 41.4(12) mb was obtained for the reaction, compared to a theoretical
prediction of 85.4 mb, hence only 48(2)% of the theoretical cross section is
exhausted. This reduction in the observed spectroscopic strength is consistent
with that found for lighter well-bound nuclei. One-neutron removal
spectroscopic factors of 0.58(11) to the ground state and 3.7(2) to all excited
states of Ni were deduced.Comment: Phys. Rev. C, accepte
On quantitative analysis of interband recombination dynamics: Theory and application to bulk ZnO
The issue of the quantitative analysis of time-resolved photoluminescence
experiments is addressed by developing and describing two approaches for
determination of unimolecular lifetime, bimolecular recombination coefficient,
and equilibrium free-carrier concentration, based on a quite general
second-order expression of the electron-hole recombination rate. Application to
the case of band-edge emission of ZnO single crystals is reported, evidencing
the signature of sub-nanosecond second-order recombination dynamics for optical
transitions close to the interband excitation edge. The resulting findings are
in good agreement with the model prediction and further confirm the presence,
formerly evidenced in literature by non-optical methods, of near-surface
conductive layers in ZnO crystals with sheet charge densities of about
3{\div}5*10^13 cm^-2Comment: 4 pages, 5 figure
Coulomb-nuclear interference in the breakup of Be
Within a theory of breakup reactions formulated in the framework of the post
form distorted wave Born approximation, we calculate contributions of the pure
Coulomb and the pure nuclear breakup as well as those of their interference
terms to a variety of cross sections in breakup reactions of the one-neutron
halo nucleus Be on a number of target nuclei. In contrast to the
assumption often made, the Coulomb-nuclear interference terms are found to be
non-negligible in case of exclusive cross sections of the fragments emitted in
this reaction on medium mass and heavy target nuclei. The consideration of the
nuclear breakup leads to a better description of such data.Comment: 9 pages, latex, 2 figures, to be published in Phys. Rev. C (Rapid
Communication
Conservative Surgical Management of Stage I Bisphosphonate-Related Osteonecrosis of the Jaw
Purpose. To report the efficacy of conservative surgical treatment for stage I bisphosphonate-related osteonecrosis of the jaw (BRONJ). Materials and Methods. This study reports the clinical outcomes of 63 patients treated for BRONJ stage I (according to Ruggiero's staging system) at the Oral Pathology and Laser-Assisted Surgery Unit of the University of Parma between January 2004 and January 2011. Surgical interventions were performed, under local analgesia, in patients unresponsive for a period of six months to noninvasive treatments such as cycles of local or systemic antibacterial therapy combined or not to low level laser therapy, ozone therapy, or Hyperbaric Oxygen Therapy. All interventions were performed after the consultation of oncologist or physician. Results. In our experience, conservative surgical treatment is associated with the highest number of BRONJ healed sites in stage I disease. Complete healing was observed in 92.6% of sites surgically treated. Conclusions. This study confirms that treatment of patients affected by minimal bone exposition, (stage I of BRONJ), through conservative surgical strategies, possibly with laser, may result in a high control of the disease in the long term
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