7,675 research outputs found
A generative model for natural sounds based on latent force modelling
Generative models based on subband amplitude envelopes of natural sounds have resulted in convincing synthesis, showing subband amplitude modulation to be a crucial component of auditory perception. Probabilistic latent variable analysis can be particularly insightful, but existing approaches don’t incorporate prior knowledge about the physical behaviour of amplitude envelopes, such as exponential decay or feedback. We use latent force modelling, a probabilistic learning paradigm that encodes physical knowledge into Gaussian process regression, to model correlation across spectral subband envelopes. We augment the standard latent force model approach by explicitly modelling dependencies across multiple time steps. Incorporating this prior knowledge strengthens the interpretation of the latent functions as the source that generated the signal. We examine this interpretation via an experiment showing that sounds generated by sampling from our probabilistic model are perceived to be more realistic than those generated by comparative models based on nonnegative matrix factorisation, even in cases where our model is outperformed from a reconstruction error perspective
Counterterms vs. Dualities
We investigate and clarify the mutual compatibility of the higher order
corrections arising in supergravity and string theory effective actions and the
non-linear duality symmetries of these theories. Starting from a conventional
tree level action leading to duality invariant equations of motion, we show how
to accommodate duality invariant counterterms given as functionals of both
electric and magnetic fields in a perturbative expansion, and to deduce from
them a non-polynomial bona fide action satisfying the Gaillard-Zumino
constraint. There exists a corresponding consistency constraint in the
non-covariant Henneaux-Teitelboim formalism which ensures that one can always
restore diffeomorphism invariance by perturbatively solving this functional
identity. We illustrate how this procedure works for the R^2 \nabla F \nabla F
and F^4 counterterms in Maxwell theory.Comment: 15 page
Genome-Wide Survey of MicroRNA - Transcription Factor Feed-Forward Regulatory Circuits in Human
In this work, we describe a computational framework for the genome-wide
identification and characterization of mixed
transcriptional/post-transcriptional regulatory circuits in humans. We
concentrated in particular on feed-forward loops (FFL), in which a master
transcription factor regulates a microRNA, and together with it, a set of joint
target protein coding genes. The circuits were assembled with a two step
procedure. We first constructed separately the transcriptional and
post-transcriptional components of the human regulatory network by looking for
conserved over-represented motifs in human and mouse promoters, and 3'-UTRs.
Then, we combined the two subnetworks looking for mixed feed-forward regulatory
interactions, finding a total of 638 putative (merged) FFLs. In order to
investigate their biological relevance, we filtered these circuits using three
selection criteria: (I) GeneOntology enrichment among the joint targets of the
FFL, (II) independent computational evidence for the regulatory interactions of
the FFL, extracted from external databases, and (III) relevance of the FFL in
cancer. Most of the selected FFLs seem to be involved in various aspects of
organism development and differentiation. We finally discuss a few of the most
interesting cases in detail.Comment: 51 pages, 5 figures, 4 tables. Supporting information included.
Accepted for publication in Molecular BioSystem
Crossings, Motzkin paths and Moments
Kasraoui, Stanton and Zeng, and Kim, Stanton and Zeng introduced certain
-analogues of Laguerre and Charlier polynomials. The moments of these
orthogonal polynomials have combinatorial models in terms of crossings in
permutations and set partitions. The aim of this article is to prove simple
formulas for the moments of the -Laguerre and the -Charlier polynomials,
in the style of the Touchard-Riordan formula (which gives the moments of some
-Hermite polynomials, and also the distribution of crossings in matchings).
Our method mainly consists in the enumeration of weighted Motzkin paths, which
are naturally associated with the moments. Some steps are bijective, in
particular we describe a decomposition of paths which generalises a previous
construction of Penaud for the case of the Touchard-Riordan formula. There are
also some non-bijective steps using basic hypergeometric series, and continued
fractions or, alternatively, functional equations.Comment: 21 page
DESIGN OF AN INTEGRATED AGRARIAN DATA DIMENSIONAL DATA WAREHOUSE
The concept of the Data warehouse was developed to provide a single access point to data from a variety of sources. There isa need to have a single location for the storage and sharing of data that users can easily utilize to make effective and qualitybusiness decisions, rather than trying to traverse the multiple data sources that exist today. Although many frameworks havebeen developed to integrate these sources into a single database, a reliable framework has yet to be developed. A majorhindrance to achieving a reliable warehouse is the poor quality of data obtained from the data transformation stage in theextract, transfer and load process. This poor quality of data contributes to inaccurate and unreliable results and if this data isused for decision making, unforeseen critical business errors can occur. This work reviews the data integration andtransformation process in dimensional data warehouses and proposes a dual structure for data integration and metadata ofmulti-formatted data used for the design of dimensional data warehouse using Agrarian data collected from Ondo State,Nigeria as a case study.Keywords: Data Warehouse, Data Integration, Metadata, Agrarian data
The SEGUE Stellar Parameter Pipeline. III. Comparison with High-Resolution Spectroscopy of SDSS/SEGUE Field Stars
We report high-resolution spectroscopy of 125 field stars previously observed
as part of the Sloan Digital Sky Survey and its program for Galactic studies,
the Sloan Extension for Galactic Understanding and Exploration (SEGUE). These
spectra are used to measure radial velocities and to derive atmospheric
parameters, which we compare with those reported by the SEGUE Stellar Parameter
Pipeline (SSPP). The SSPP obtains estimates of these quantities based on SDSS
ugriz photometry and low-resolution (R = 2000) spectroscopy. For F- and G-type
stars observed with high signal-to-noise ratios (S/N), we empirically determine
the typical random uncertainties in the radial velocities, effective
temperatures, surface gravities, and metallicities delivered by the SSPP to be
2.4 km/s, 130 K (2.2%), 0.21 dex, and 0.11 dex, respectively, with systematic
uncertainties of a similar magnitude in the effective temperatures and
metallicities. We estimate random errors for lower S/N spectra based on
numerical simulations.Comment: 37 pages, 6 tables, 6 figures, submitted to the Astronomical Journa
Metastatic breast carcinoma in the mandible presenting as a periodontal abscess: a case report
<p>Abstract</p> <p>Introduction</p> <p>Tumors can metastasize to the oral cavity and affect the jaws, soft tissue and salivary glands. Oral cavity metastases are considered rare and represent approximately 1% of all oral malignancies. Because of their rarity and atypical clinical and radiographic appearance, metastatic lesions are considered a diagnostic challenge. The purpose of this report is to present a rare case of a metastatic breast carcinoma mimicking a periodontal abscess in the mandible.</p> <p>Case presentation</p> <p>A 55-year-old Caucasian woman was referred to our clinic for evaluation of bisphosphonate-induced jaw osteonecrosis. She had undergone modified radical mastectomy with axillary lymph node dissection for invasive ductal carcinoma of the left breast. Her clinical examination showed diffuse swelling and a periodontal pocket of 6 mm exhibiting suppuration in the posterior right mandible. Moreover, paresthesia of the lower right lip and chin was noted. There were no significant radiographic findings other than alveolar bone loss due to her periodontal disease. Although the lesion resembled a periodontal abscess, metastatic carcinoma of the breast was suspected on the basis of the patient's medical history. The area was biopsied, and histological analysis confirmed the final diagnosis of metastatic breast carcinoma.</p> <p>Conclusion</p> <p>The general dentist or dental specialist should maintain a high level of suspicion while evaluating patients with a history of cancer. Paresthesias of the lower lip and the chin should be considered ominous signs of metastatic disease. This case highlights the importance of the value of a detailed medical history and thorough clinical examination for the early detection of metastatic tumors in the oral cavity.</p
In vitro assessment of the performance of a new multiband mucosectomy device for endoscopic resection of early upper gastrointestinal neoplasia
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Association of common genetic variants with risperidone adverse events in a Spanish schizophrenic population
Risperidone non-compliance is often high due to undesirable side effects, whose development is in part genetically determined. Studies with genetic variants involved in the pharmacokinetics and pharmacodynamics of risperidone have yielded inconsistent results. Thus, the aim of this study was to investigate the putative association of genetic markers with the occurrence of four frequently observed adverse events secondary to risperidone treatment: sleepiness, weight gain, extrapyramidal symptoms and sexual adverse events. A series of 111 schizophrenia inpatients were genotyped for genetic variants previously associated with or potentially involved in risperidone response. Presence of adverse events was the main variable and potential confounding factors were considered. Allele 16Gly of ADRB2 was significantly associated with a higher risk of sexual adverse events. There were other non-significant trends for DRD3 9Gly and SLC6A4 S alleles. Our results, although preliminary, provide new candidate variants of potential use in risperidone safety prediction
Mini-laparoscopic versus laparoscopic approach to appendectomy
BACKGROUND: The purpose of this clinical study is to evaluate the feasibility of using 2-mm laparoscopic instruments to perform an appendectomy in patients with clinically suspected acute appendicitis and compare the outcome of this mini-laparoscopic or "needlescopic" approach to the conventional laparoscopic appendectomy. METHODS: Two groups of patients undergoing appendectomy over 24 months were studied. In the first group, needlescopic appendectomy was performed in 15 patients by surgeons specializing in advanced laparoscopy. These patients were compared with the second or control group that included 21 consecutive patients who underwent laparoscopic appendectomy. We compared the patients' demographic data, operative findings, complications, postoperative pain medicine requirements, length of hospital stay, and recovery variables. Differences were considered statistically significant at a p-value < 0.05. RESULTS: Patient demographics, history of previous abdominal surgery, and operative findings were similar in both groups. There was no conversion to open appendectomy in either group. No postoperative morbidity or mortality occurred in either group. The needlescopic group had a significantly shorter mean operative time (p = 0.02), reduced postoperative narcotics requirements (p = 0.05), shorter hospital stay (p = 0.04), and quicker return to work (p = 0.03) when compared with the laparoscopic group. CONCLUSIONS: We conclude that the needlescopic technique is a safe and effective approach to appendectomy. When performed by experienced laparoscopic surgeons, the needlescopic technique results in significantly shorter postoperative convalescence and a prompt recovery
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