Associação Brasileira de Estatística
Repositório da Produção USP (Univ. de São Paulo)Not a member yet
45573 research outputs found
Sort by
Efficient self-similarity range wide-joins fostering near-duplicate image detection in emergency scenarios
No full textCrowdsourcing information is being increasingly employed to improve and support decision making in emergency situations. However, the gathered records quickly become too similar among themselves and handling several similar reports does not add valuable knowledge to assist the helping personnel at the control center in their decision making tasks. The usual approaches to detect and handle the so-called near-duplicate data rely on costly twofold processing. Aimed at reducing the cost and also improving the ability of duplication detection, we developed a framework model based on the similarity wide-join database operator. We extended the wide-join definition empowering it to surpass its restrictions and accomplish the near-duplicate task too. In this paper, we also provide an efficient algorithm based on pivots that speeds up the entire process, which enables retrieving the top similar elements in a single-pass processing. Experiments using real datasets show that our framework is up to three orders of magnitude faster than the competing techniques in the literature, whereas also improving the quality of the result in about 35 percent.FAPESPCNPQCAPESRescuer (EU FP7-614154 / CNPQ 490084/2013-3
Identification and characterization of putative xylose and cellobiose transporters in Aspergillus nidulans
No full textAbstract\ud
\ud
Background\ud
The conversion of lignocellulosic biomass to biofuels (second-generation biofuel production) is an environmentally friendlier alternative to petroleum-based energy sources. Enzymatic deconstruction of lignocellulose, catalyzed by filamentous fungi such as Aspergillus nidulans, releases a mixture of mono- and polysaccharides, including hexose (glucose) and pentose (xylose) sugars, cellodextrins (cellobiose), and xylooligosaccharides (xylobiose). These sugars can subsequently be fermented by yeast cells to ethanol. One of the major drawbacks in this process lies in the inability of yeast, such as Saccharomyces cerevisiae, to successfully internalize sugars other than glucose. The aim of this study was, therefore, to screen the genome of A. nidulans, which encodes a multitude of sugar transporters, for transporters able to internalize non-glucose sugars and characterize them when introduced into S. cerevisiae.\ud
\ud
\ud
Results\ud
This work identified two proteins in A. nidulans, CltA and CltB, with roles in cellobiose transport and cellulose signaling, respectively. CltA, when introduced into S. cerevisiae, conferred growth on low and high concentrations of cellobiose. Deletion of cltB resulted in reduced growth and extracellular cellulase activity in A. nidulans in the presence of cellobiose. CltB, when introduced into S. cerevisiae, was not able to confer growth on cellobiose, suggesting that this protein is a sensor rather than a transporter. However, we have shown that the introduction of additional functional copies of CltB increases the growth in the presence of low concentrations of cellobiose, strongly indicating CltB is able to transport cellobiose. Furthermore, a previously identified glucose transporter, HxtB, was also found to be a major xylose transporter in A. nidulans. In S. cerevisiae, HxtB conferred growth on xylose which was accompanied by ethanol production.\ud
\ud
\ud
Conclusions\ud
This work identified a cellobiose transporter, a xylose transporter, and a putative cellulose transceptor in A. nidulans. This is the first time that a sensor role for a protein in A. nidulans has been proposed. Both transporters are also able to transport glucose, highlighting the preference of A. nidulans for this carbon source. This work provides a basis for future studies which aim at characterizing and/or genetically engineering Aspergillus spp. transporters, which, in addition to glucose, can also internalize other carbon sources, to improve transport and fermentation of non-glucose sugars in S. cerevisiae.We would like to thank the Conselho Nacional de Desenvolvimento Científico\ud
e Tecnológico (CNPq) and the Fundação de Amparo à Pesquisa do Estado de\ud
São Paulo (FAPESP) in Brazil for funding this research
On the support of a similarity-enabled relational database management system in civilian crisis situations
No full textCrowdsourcing solutions can be helpful to extract information from disaster-related data during crisis management. However, certain information can only be obtained through similarity operations. Some of them also depend on additional data stored in a Relational Database Management System (RDBMS). In this context, several works focus on crisis management supported by data. Nevertheless, none of them provide a methodology for employing a similarity-enabled RDBMS in disaster-relief tasks. To fill this gap, we introduce a methodology together with the Data-Centric Crisis Management (DCCM) architecture, which employs our methods over a similarity-enabled RDBMS. We evaluate our proposal through three tasks: classification of incoming data regarding current events, identifying relevant information to guide rescue teams; filtering of incoming data, enhancing the decision support by removing near-duplicate data; and similarity retrieval of historical data, supporting analytical comprehension of the crisis context. To make it possible, similarity-based operations were implemented within one popular, open-source RDBMS. Results using real data from Flickr show that our proposal is feasible for real-time applications. In addition to high performance, accurate results were obtained with a proper combination of techniques for each task. Hence, we expect our work to provide a framework for further developments on crisis management solutions.FAPESPCAPESCNPqRESCUER project, funded by the European Commission (Grant: 614154
Epigenetic evidence for involvement of the oxytocin receptor gene in obsessive–compulsive disorder
No full textAbstract\ud
\ud
Background\ud
\ud
Obsessive–compulsive disorder (OCD) is a chronic neurodevelopmental disorder that affects up to 3% of the general population. Although epigenetic mechanisms play a role in neurodevelopment disorders, epigenetic pathways associated with OCD have rarely been investigated. Oxytocin is a neuropeptide involved in neurobehavioral functions. Oxytocin has been shown to be associated with the regulation of complex socio-cognitive processes such as attachment, social exploration, and social recognition, as well as anxiety and other stress-related behaviors. Oxytocin has also been linked to the pathophysiology of OCD, albeit inconsistently. The aim of this study was to investigate methylation in two targets sequences located in the exon III of the oxytocin receptor gene (OXTR), in OCD patients and healthy controls. We used bisulfite sequencing to quantify DNA methylation in peripheral blood samples collected from 42 OCD patients and 31 healthy controls.\ud
\ud
\ud
\ud
Results\ud
We found that the level of methylation of the cytosine-phosphate-guanine sites in two targets sequences analyzed was greater in the OCD patients than in the controls. The higher methylation in the OCD patients correlated with OCD severity. We measured DNA methylation in the peripheral blood, which prevented us from drawing any conclusions about processes in the central nervous system.\ud
\ud
\ud
Conclusion\ud
To our knowledge, this is the first study investigating DNA methylation of the OXTR in OCD. Further studies are needed to evaluate the roles that DNA methylation and oxytocin play in OCD.This work was supported by grants from the Fundação de Amparo à Pesquisa\ud
do Estado de São Paulo (FAPESP, São Paulo Research Foundation—Process:\ud
2008/11537-7 and Process: 2014/01585-5)
Physicians’ job satisfaction and motivation in a public academic hospital
No full textAbstract\ud
\ud
Background\ud
Physician shortage is a global issue that concerns Brazil’s authorities. The organizational structure and the environment of a medical institution can hide a low-quality life of a physician. This study examines the relationship between the hospital work environment and physicians’ job satisfaction and motivation when working in a large public academic hospital.\ud
\ud
\ud
Methods\ud
The study was restricted to one large, multispecialty Brazil’s hospital. Six hundred hospital physicians were invited to participate by e-mail. A short version of the Physician Worklife Survey (PWS) was used to measure working satisfaction. Physicians were also asked for socio-demographic information, medical specialty, and the intention to continue working in the hospital.\ud
\ud
\ud
Results\ud
Data from 141 questionnaires were included in the analyses. Forty-five physicians graduated from the hospital’s university, and they did not intend to leave the hospital under any circumstance (affective bond). The motivating factor for beginning the career at the hospital and to continue working there were the connection to the medical school and the hospital status as a “prestigious academic hospital”; the physicians were more satisfied with the career than the specialty. Only 30% completely agreed with the statement “If I had to start my career over again, I would choose my current specialty,” while 45% completely agreed with the statement “I am not well compensated given my training and experience.” The greater point of satisfaction was the relationship with physician colleagues. They are annoyed about the amount of calls they are requested to take and about how work encroaches on their personal time. No significant differences between medical specialties were found in the analysis.\ud
\ud
\ud
Conclusions\ud
The participants were satisfied with their profession. The fact that they remained at the hospital was related to the academic environment, the relationship with colleagues, and the high prestige in which society holds the institution. The points of dissatisfaction were inadequate remuneration and the fact that work invaded personal time. Routinely, there is a need for organizations to examine the impact of their structures, policies, and procedures on the stress and quality of life of physicians
RETRACTED ARTICLE: Fatal factitious Cushing\ud syndrome (Münchhausen’s syndrome) in a patient with macroprolactinoma and silent\ud corticotrophinoma: case report and literature review
No full textAbstract\ud
Münchhausen’s syndrome (MS) is a chronic factitious disorder\ud
characterized by the intentional production of clinical symptoms without external\ud
incentive. One type of MS is factitious Cushing syndrome, an extremely rare clinical\ud
situation in which the diagnosis is challenging mainly due to interference of the\ud
exogenous medication in cortisol immunoassays. We described a 26-year-old woman who\ud
was originally diagnosed with a macroprolactinoma and during follow-up developed\ud
clinical and laboratorial hypercortisolism. A transsphenoidal surgery was performed\ud
and immunohistochemistry revealed positive and diffuse staining for both hormones.\ud
Four years later, her hypercortisolism recurred and the confirmation of factitious\ud
Cushing syndrome was delayed due to conflicting laboratorial results.\ud
There are few cases in the literature of factitious Cushing syndrome,\ud
and only one had a fatal outcome. The diagnosis of this condition is complex and\ud
includes cyclic Cushing syndrome in the differential diagnosis. These patients have\ud
high morbidity and increased mortality risk and are likely to have other psychiatric\ud
disorders. Prednisone was identified as the culprit in the majority of the\ud
cases.We would like to thank Dr. Wagner Farid Gattaz and Dr. Jose Gallucci Neto,\ud
from the Psychiatric Division, for providing assistance during hospitalization.\ud
This work was partially supported by grants from Conselho Nacional de\ud
Desenvolvimento Científico e Tecnológico – CNPq (301339/2008-9 to B.B.M.)
Transcriptional profiling of Saccharomyces cerevisiae exposed to propolis
No full textAbstract
Background
Propolis is a natural product of plant resins collected by honeybees (Apis mellifera) from various plant sources. Our previous studies indicated that propolis sensitivity is dependent on the mitochondrial function and that vacuolar acidification and autophagy are important for yeast cell death caused by propolis. Here, we extended our understanding of propolis-mediated cell death in the yeast Saccharomyces cerevisiae by applying systems biology tools to analyze the transcriptional profiling of cells exposed to propolis.
Methods
We have used transcriptional profiling of S. cerevisiae exposed to propolis. We validated our findings by using real-time PCR of selected genes. Systems biology tools (physical protein-protein interaction [PPPI] network) were applied to analyse the propolis-induced transcriptional bevavior, aiming to identify which pathways are modulated by propolis in S. cerevisiae and potentially influencing cell death.
Results
We were able to observe 1,339 genes modulated in at least one time point when compared to the reference time (propolis untreated samples) (t- test, p- value 0.01). Enrichment analysis performed by Gene Ontology (GO) Term finder tool showed enrichment for several biological categories among the genes up-regulated in the microarray hybridization such as transport and transmembrane transport and response to stress. Real-time RT-PCR analysis of selected genes showed by our microarray hybridization approach was capable of providing information about S. cerevisiae gene expression modulation with a considerably high level of confidence. Finally, a physical protein-protein (PPPI) network design and global topological analysis stressed the importance of these pathways in response of S. cerevisiae to propolis and were correlated with the transcriptional data obtained thorough the microarray analysis.
Conclusions
In summary, our data indicate that propolis is largely affecting several pathways in the eukaryotic cell. However, the most prominent pathways are related to oxidative stress, mitochondrial electron transport chain, vacuolar acidification, regulation of macroautophagy associated with protein target to vacuole, cellular response to starvation, and negative regulation of transcription from RNA polymerase II promoter. Our work emphasizes again the importance of S. cerevisiae as a model system to understand at molecular level the mechanism whereby propolis causes cell death in this organism at the concentration herein tested. Our study is the first one that investigates systematically by using functional genomics how propolis influences and modulates the mRNA abundance of an organism and may stimulate further work on the propolis-mediated cell death mechanisms in fungi
Mutation spectrum in South American Lynch syndrome families
No full textAbstract
Background
Genetic counselling and testing for Lynch syndrome have recently been introduced in several South American countries, though yet not available in the public health care system.
Methods
We compiled data from publications and hereditary cancer registries to characterize the Lynch syndrome mutation spectrum in South America. In total, data from 267 families that fulfilled the Amsterdam criteria and/or the Bethesda guidelines from Argentina, Brazil, Chile, Colombia and Uruguay were included.
Results
Disease-predisposing mutations were identified in 37% of the families and affected MLH1 in 60% and MSH2 in 40%. Half of the mutations have not previously been reported and potential founder effects were identified in Brazil and in Colombia.
Conclusion
The South American Lynch syndrome mutation spectrum includes multiple new mutations, identifies potential founder effects and is useful for future development of genetic testing in this continent
Texture evolution in the\ud Fe-30.5Mn-8.0Al-1.2C\ud and Fe-30.5Mn-2.1Al-1.2C\ud steels upon cold rolling
No full textCrystallographic textures of the austenitic low-density Fe-30.5Mn-8.0Al-1.2C\ud
(8Al) and Fe-30.5Mn-2.1Al-1.2C (2Al) (wt.%) steels were examined during cold\ud
rolling by means of electron backscatter diffraction (EBSD) and electron channeling\ud
contrast imaging (ECCI). Random oriented grains orient towards Goss- and\ud
brass-components along the α-fiber as the strain increased, with activation of slip,\ud
mechanical twinning, and shear banding, for both steels. S- and copper-orientations\ud
were also observed in the 8Al steel at 50% reduction. The route of Cu-CuT-Gossbrass\ud
texture evolution was found in the 2Al alloy. Cu, Goss, and brass textures\ud
occur as a dominant texture in the deformed 8Al alloy. Copper-type texture accompanied\ud
with slip at low reduction (20%), as well as Cu-type shear bands, and shear\ud
banding inside Goss-oriented grains at higher reduction (50%), were observed in the\ud
8Al steel. It is suggested that this copper-type rolling texture may be attributed to\ud
the Al addition, which contributes to its low twinning activity compared to that in\ud
the 2Al alloy. Cu-CuT-brass f.c.c. rolling texture transition to form the Brass-type\ud
texture was observed at higher reduction in the 2Al alloy with strong similarity to\ud
that found in other Fe-Mn-C system TWIP steels.CNP
The Nanocrystalline SnO2–TiO2 System—Part I: Structural Features
No full textThe phases present and their crystal structure and microstructure in the nanocrystalline SnO2–TiO2 system were studied in the compositional range Sn1−xTixO2 (0.0 ≤ x ≤ 0.9). There is an apparent increase in the solubility limits in the solid solution compared to bulk crystalline SnO2–TiO2. No two phase region was observed with increasing TiO2 content. Electron energy loss spectroscopy, infrared spectroscopy (FTIR), and X-ray diffraction (XRD) of the nanopowders showed that the apparent increase in solubility is related to the systematic Ti4+ segregation on the particle surface (surface excess) at the SnO2-rich side, avoiding the nucleation of a second phase even at high Ti4+ contents. Is this finding in accord with Raman spectra, which suggest localized Ti-rich sites in the absence of a second crystalline phase. Ti4+ surface excess is also lead to a modification of the surface hydroxyls and a decrease in the crystallite size of the nanoparticles (with a concomitant increase in surface area), with expected implications to catalytic and sensorial properties of these nanoparticles.CAPESCNP