1,393 research outputs found
A Scalable Feature Selection and Opinion Miner Using Whale Optimization Algorithm
Due to the fast-growing volume of text documents and reviews in recent years,
current analyzing techniques are not competent enough to meet the users' needs.
Using feature selection techniques not only support to understand data better
but also lead to higher speed and also accuracy. In this article, the Whale
Optimization algorithm is considered and applied to the search for the optimum
subset of features. As known, F-measure is a metric based on precision and
recall that is very popular in comparing classifiers. For the evaluation and
comparison of the experimental results, PART, random tree, random forest, and
RBF network classification algorithms have been applied to the different number
of features. Experimental results show that the random forest has the best
accuracy on 500 features. Keywords: Feature selection, Whale Optimization
algorithm, Selecting optimal, Classification algorith
Demonstration of a Melanoma-Specific CD44 Alternative Splicing Pattern That Remains Qualitatively Stable, but Shows Quantitative Changes during Tumour Progression
The role of CD44 in the progression of human melanoma has mostly been characterised by qualitative changes in
expression of its individual variable exons. These exons however, may be expressed to form a number of molecules, the
alternative splice variants of CD44, which may be structurally and functionally different. Using real-time PCR measurements
with variable exon specific primers we have determined that all are expressed in human melanoma. To permit comparison
between different tumours we identified a stable CD44 variable exon (CD44v) expression pattern, or CD44 âfingerprintâ. This
was found to remain unchanged in melanoma cell lines cultured in different matrix environments. To evaluate evolution of
this fingerprint during tumour progression we established a scid mouse model, in which the pure expression pattern of
metastatic primary tumours, circulating cells and metastases, non-metastatic primary tumours and lung colonies could be
studied. Our analyses demonstrated, that although the melanoma CD44 fingerprint is qualitatively stable, quantitative
changes are observed suggesting a possible role in tumour progression
Multiple Distant Origins for Green Sea Turtles Aggregating off Gorgona Island in the Colombian Eastern Pacific
Mitochondrial DNA analyses have been useful for resolving maternal lineages and migratory behavior to foraging grounds (FG) in sea turtles. However, little is known about source rookeries and haplotype composition of foraging green turtle aggregations in the southeastern Pacific. We used mitochondrial DNA control region sequences to identify the haplotype composition of 55 green turtles, Chelonia mydas, captured in foraging grounds of Gorgona National Park in the Colombian Pacific. Amplified fragments of the control region (457 bp) revealed the presence of seven haplotypes, with haplotype (h) and nucleotide (Ď) diversities of hâ=â0.300Âą0.080 and Ďâ=â0.009Âą0.005 respectively. The most common haplotype was CMP4 observed in 83% of individuals, followed by CMP22 (5%). The genetic composition of the Gorgona foraging population primarily comprised haplotypes that have been found at eastern Pacific rookeries including Mexico and the Galapagos, as well as haplotypes of unknown stock origin that likely originated from more distant western Pacific rookeries. Mixed stock analysis suggests that the Gorgona FG population is comprised mostly of animals from the Galapagos rookery (80%). Lagrangian drifter data showed that movement of turtles along the eastern Pacific coast and eastward from distant western and central Pacific sites was possible through passive drift. Our results highlight the importance of this protected area for conservation management of green turtles recruited from distant sites along the eastern Pacific Ocean
Epidemiology of acute kidney injury in Hungarian intensive care units: a multicenter, prospective, observational study
<p>Abstract</p> <p>Background</p> <p>Despite the substantial progress in the quality of critical care, the incidence and mortality of acute kidney injury (AKI) continues to rise during hospital admissions. We conducted a national, multicenter, prospective, epidemiological survey to evaluate the importance of AKI in intensive care units (ICUs) in Hungary. The objectives of this study were to determine the incidence of AKI in ICU patients; to characterize the differences in aetiology, illness severity and clinical practice; and to determine the influencing factors of the development of AKI and the patients' outcomes.</p> <p>Methods</p> <p>We analysed the demographic, morbidity, treatment modality and outcome data of patients (n = 459) admitted to ICUs between October 1<sup>st</sup>, 2009 and November 30<sup>th</sup>, 2009 using a prospectively filled in electronic survey form in 7 representative ICUs.</p> <p>Results</p> <p>The major reason for ICU admission was surgical in 64.3% of patients and medical in the remaining 35.7%. One-hundred-twelve patients (24.4%) had AKI. By AKIN criteria 11.5% had Stage 1, 5.4% had Stage 2 and 7.4% had Stage 3. In 44.0% of patients, AKI was associated with septic shock. Vasopressor treatment, SAPS II score, serum creatinine on ICU admission and sepsis were the independent risk factors for development of any stage of AKI. Among the Stage 3 patients (34) 50% received renal replacement therapy. The overall utilization of intermittent renal replacement therapy was high (64.8%). The overall in-hospital mortality rate of AKI was 49% (55/112). The ICU mortality rate was 39.3% (44/112). The independent risk factors for ICU mortality were age, mechanical ventilation, SOFA score and AKI Stage 3.</p> <p>Conclusions</p> <p>For the first time we have established the incidence of AKI using the AKIN criteria in Hungarian ICUs. Results of the present study confirm that AKI has a high incidence and is associated with high ICU and in-hospital mortality.</p
Active microrheology and simultaneous visualization of sheared phospholipid monolayers
Two-dimensional films of surface-active agentsâfrom phospholipids and proteins to nanoparticles and colloidsâstabilize fluid interfaces, which are essential to the science, technology and engineering of everyday life. The 2D nature of interfaces present unique challenges and opportunities: coupling between the 2D films and the bulk fluids complicates the measurement of surface dynamic properties, but allows the interfacial microstructure to be directly visualized during deformation. Here we present a novel technique that combines active microrheology with fluorescence microscopy to visualize fluid interfaces as they deform under applied stress, allowing structure and rheology to be correlated on the micron-scale in monolayer films. We show that even simple, single-component lipid monolayers can exhibit viscoelasticity, history dependence, a yield stress and hours-long time scales for elastic recoil and aging. Simultaneous visualization of the monolayer under stress shows that the rich dynamical response results from the cooperative dynamics and deformation of liquid-crystalline domains and their boundaries
Misbehaviour of XIST RNA in Breast Cancer Cells
A role of X chromosome inactivation process in the development of breast cancer have been suggested. In particular, the relationship between the breast cancer predisposing gene BRCA1 and XIST, the main mediator of X chromosome inactivation, has been intensely investigated, but still remains controversial. We investigated this topic by assessing XIST behaviour in different groups of breast carcinomas and in a panel of breast cancer cell lines both BRCA1 mutant and wild type. In addition, we evaluated the occurrence of broader defects of heterochromatin in relation to BRCA1 status in breast cancer cells. We provide evidence that in breast cancer cells BRCA1 is involved in XIST regulation on the active X chromosome, but not in its localization as previously suggested, and that XIST can be unusually expressed by an active X and can decorate it. This indicates that the detection of XIST cloud in cancer cell is not synonymous of the presence of an inactive X chromosome. Moreover, we show that global heterochromatin defects observed in breast tumor cells are independent of BRCA1 status. Our observations sheds light on a possible previously uncharacterized mechanism of breast carcinogenesis mediated by XIST misbehaviour, particularly in BRCA1-related cancers. Moreover, the significant higher levels of XIST-RNA detected in BRCA1-associated respect to sporadic basal-like cancers, opens the possibility to use XIST expression as a marker to discriminate between the two groups of tumors
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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A Search for Dark Higgs Bosons
Recent astrophysical and terrestrial experiments have motivated the proposal
of a dark sector with GeV-scale gauge boson force carriers and new Higgs
bosons. We present a search for a dark Higgs boson using 516 fb-1 of data
collected with the BABAR detector. We do not observe a significant signal and
we set 90% confidence level upper limits on the product of the Standard
Model-dark sector mixing angle and the dark sector coupling constant.Comment: 7 pages, 5 postscript figures, published version with improved plots
for b/w printin
X-ray emission from the Sombrero galaxy: discrete sources
We present a study of discrete X-ray sources in and around the
bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival
Chandra observations with a total exposure of ~200 ks. With a detection limit
of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30
kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler
et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS
observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray
binaries (LMXBs). We quantify the differential luminosity functions (LFs) for
both the detected GC and field LMXBs, whose power-low indices (~1.1 for the
GC-LF and ~1.6 for field-LF) are consistent with previous studies for
elliptical galaxies. With precise sky positions of the GCs without a detected
X-ray source, we further quantify, through a fluctuation analysis, the GC LF at
fainter luminosities down to 1E35 erg/s. The derived index rules out a
faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent
findings in several elliptical galaxies and the bulge of M31. On the other
hand, the 2-6 keV unresolved emission places a tight constraint on the field
LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101
sources in the halo of Sombrero. The presence of these sources cannot be
interpreted as galactic LMXBs whose spatial distribution empirically follows
the starlight. Their number is also higher than the expected number of cosmic
AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray
surveys. We suggest that either the cosmic X-ray background is unusually high
in the direction of Sombrero, or a distinct population of X-ray sources is
present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres
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