2,588 research outputs found
Aging and Rejuvenation with Fractional Derivatives
We discuss a dynamic procedure that makes the fractional derivatives emerge
in the time asymptotic limit of non-Poisson processes. We find that two-state
fluctuations, with an inverse power-law distribution of waiting times, finite
first moment and divergent second moment, namely with the power index mu in the
interval 2<mu <3, yields a generalized master equation equivalent to the sum of
an ordinary Markov contribution and of a fractional derivative term. We show
that the order of the fractional derivative depends on the age of the process
under study. If the system is infinitely old, the order of the fractional
derivative, ord, is given by ord=3-mu . A brand new system is characterized by
the degree ord=mu -2. If the system is prepared at time -ta<0$ and the
observation begins at time t=0, we derive the following scenario. For times
0<t<<ta the system is satisfactorily described by the fractional derivative
with ord=3-mu . Upon time increase the system undergoes a rejuvenation process
that in the time limit t>>ta yields ord=mu -2. The intermediate time regime is
probably incompatible with a picture based on fractional derivatives, or, at
least, with a mono-order fractional derivative.Comment: 11 pages, 4 figure
Primary cosmic ray spectrum in the 10 to the 12th power - 10 to the 16th power eV energy range from the NUSEX experiment
A primary cosmic ray spectrum was derived which fits both experimental multiple muon rates and the all-nucleon flux derived from the single muon intensities underground. In the frame of the interaction model developed by Gaisser, Elbert and Stanev, it is possible to reproduce NUSEX muon data with a primary composition in which the iron spectrum is only slightly flatter than the proton one. This result rules out the popular idea that the primary composition varies drastically with increasing energy, leading to the dominance of heavier nuclei at energies 10 to the 15th power to 10 to the 16th power eV
Photometric Redshifts for Galaxies in the GOODS Southern Field
We use extensive multi-wavelength photometric data from the Great
Observatories Origins Deep Survey (GOODS) to estimate photometric redshifts for
a sample of 434 galaxies with spectroscopic redshifts in the Chandra Deep Field
South. Using the Bayesian method, which incorporates redshift/magnitude priors,
we estimate photometric redshifts for galaxies in the range 18 < R (AB) < 25.5,
giving an rms scatter of 0.11. The outlier fraction is < 10%, with the
outlier-clipped rms being 0.047. We examine the accuracy of photometric
redshifts for several, special sub--classes of objects. The results for
extremely red objects are more accurate than those for the sample as a whole,
with rms of 0.051 and very few outliers (3%). Photometric redshifts for active
galaxies, identified from their X-ray emission, have a dispersion of 0.104,
with 10% outlier fraction, similar to that for normal galaxies. Employing a
redshift/magnitude prior in this process seems to be crucial in improving the
agreement between photometric and spectroscopic redshifts.Comment: Accepted for publication in ApJ
Levy flights from a continuous-time process
The Levy-flight dynamics can stem from simple random walks in a system whose
operational time (number of steps n) typically grows superlinearly with
physical time t. Thus, this processes is a kind of continuous-time random walks
(CTRW), dual to usual Scher-Montroll model, in which grows sublinearly with
t. The models in which Levy-flights emerge due to a temporal subordination let
easily discuss the response of a random walker to a weak outer force, which is
shown to be nonlinear. On the other hand, the relaxation of en ensemble of such
walkers in a harmonic potential follows a simple exponential pattern and leads
to a normal Boltzmann distribution. The mixed models, describing normal CTRW in
superlinear operational time and Levy-flights under the operational time of
subdiffusive CTRW lead to paradoxical diffusive behavior, similar to the one
found in transport on polymer chains. The relaxation to the Boltzmann
distribution in such models is slow and asymptotically follows a power-law
Machine learning algorithms distinguish discrete digital emotional fingerprints for web pages related to back pain
Back pain is the leading cause of disability worldwide. Its emergence relates not only to the musculoskeletal degeneration biological substrate but also to psychosocial factors; emotional components play a pivotal role. In modern society, people are significantly informed by the Internet; in turn, they contribute social validation to a “successful” digital information subset in a dynamic interplay. The Affective component of medical pages has not been previously investigated, a significant gap in knowledge since they represent a critical biopsychosocial feature. We tested the hypothesis that successful pages related to spine pathology embed a consistent emotional pattern, allowing discrimination from a control group. The pool of web pages related to spine or hip/knee pathology was automatically selected by relevance and popularity and submitted to automated sentiment analysis to generate emotional patterns. Machine Learning (ML) algorithms were trained to predict page original topics from patterns with binary classification. ML showed high discrimination accuracy; disgust emerged as a discriminating emotion. The findings suggest that the digital affective “successful content” (collective consciousness) integrates patients’ biopsychosocial ecosystem, with potential implications for the emergence of chronic pain, and the endorsement of health-relevant specific behaviors. Awareness of such effects raises practical and ethical issues for health information providers
Analysis of residual acrylamide in field crops
Polyacrylamide (PAM) is a widely used product for a large number
of applications. Many of the emerging applications are in the area
of agriculture. PAM is blended with pesticides as a thickening
agent, added to irrigation water to minimize soil erosion, and used
as a medium for hydroponically grown crops. Although PAM is
stable and considered to be safe, residual acrylamide (AMD)
monomer is a neurotoxin and animal carcinogen. In this work,
residual AMD is analyzed in a variety of crops that were grown
under PAM treatment to stabilize soil erosion. Corn, potatoes,
sugar beets, and beans are analyzed for AMD. A sample of the crop
is homogenized with water, and the water layer is filtered and
derivatized with bromine to form 2,3-dibromopropionamide. The
derivative is then extracted with ethyl acetate and converted to the
more stable 2-propenamide prior to gas chromatographic analysis
using an electron capture detector. Capillary Carbowax columns
were used. All tested crops show < 10 ppb AMD. Furthermore, it
seems that AMD is not stable when it comes in contact with the
crop tissues. In the presence of plant tissues, AMD will disappear as
a function of time. Beans blended with 100 ppb AMD for 10 min
yield a recovery of only 22%. For a bean sample that was soaked
with 500 ppb AMD solution for 18 h, the recovery is 7%. Other
crops show different AMD recoveries
Detection of MicroRNA processing intermediates through RNA ligation approaches
MicroRNAs (miRNA) are small RNAs of 20–22 nt that regulate diverse biological pathways through the modulation of gene expression. miRNAs recognize target RNAs by base complementarity and guide them to degradation or translational arrest. They are transcribed as longer precursors with extensive secondary structures. In plants, these precursors are processed by a complex harboring DICER-LIKE1 (DCL1), which cuts on the precursor stem region to release the mature miRNA together with the miRNA*. In both plants and animals, the miRNA precursors contain spatial clues that determine the position of the miRNA along their sequences. DCL1 is assisted by several proteins, such as the double-stranded RNA binding protein, HYPONASTIC LEAVES1 (HYL1), and the zinc finger protein SERRATE (SE). The precise biogenesis of miRNAs is of utter importance since it determines the exact nucleotide sequence of the mature small RNAs and therefore the identity of the target genes. miRNA processing itself can be regulated and therefore can determine the final small RNA levels and activity. Here, we describe methods to analyze miRNA processing intermediates in plants. These approaches can be used in wild-type or mutant plants, as well as in plants grown under different conditions, allowing a molecular characterization of the miRNA biogenesis from the RNA precursor perspective.Fil: Moro, BelĂ©n. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Rosario. Instituto de BiologĂa Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias BioquĂmicas y FarmacĂ©uticas. Instituto de BiologĂa Molecular y Celular de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias BioquĂmicas y FarmacĂ©uticas; ArgentinaFil: Rojas, Arantxa Maria Larisa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Rosario. Instituto de BiologĂa Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias BioquĂmicas y FarmacĂ©uticas. Instituto de BiologĂa Molecular y Celular de Rosario; ArgentinaFil: Palatnik, Javier Fernando. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Rosario. Instituto de BiologĂa Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias BioquĂmicas y FarmacĂ©uticas. Instituto de BiologĂa Molecular y Celular de Rosario; Argentina. Universidad Nacional de Rosario. Centro de Estudios Interdisciplinarios; Argentin
PD-L1 up-regulation in melanoma increases disease aggressiveness and is mediated through miR-17-5p
PD-L1 is expressed by a subset of patients with metastatic melanoma (MM) with an unfavorable outcome. Its expression is increased in cells resistant to BRAF or MEK inhibitors (BRAFi or MEKi). However, the function and regulation of expression of PD-L1 remain incompletely understood. After generating BRAFi- and MEKi-resistant cell lines, we observed marked up-regulation of PD-L1 expression. These cells were characterized by a common gene expression profile with up-regulation of genes involved in cell movement. Consistently, in vitro they showed significantly increased invasive properties. This phenotype was controlled in part by PD-L1, as determined after silencing the molecule. Up-regulation of PD-L1 was due to post-transcriptional events controlled by miR-17-5p, which showed an inverse correlation with PD-L1 mRNA. Direct binding between miR-17-5p and the 3’-UTR of PD-L1 mRNA was demonstrated using luciferase reporter assays. In a cohort of 80 BRAF-mutated MM patients treated with BRAFi or MEKi, constitutive expression of PD-L1 in the absence of immune infiltrate, defined the patient subset with the worst prognosis. Furthermore, PD-L1 expression increased in tissue biopsies after the metastatic lesions became resistant to BRAFi or MEKi. Lastly, plasmatic miR-17-5p levels were higher in patients with PD-L1(+) than PD-L1(-) lesions. In conclusion, our findings indicate that PD-L1 expression induces a more aggressive behavior in melanoma cells. We also show that PD-L1 up-regulation in BRAFi or MEKi-resistant cells is partly due to post-transcriptional mechanisms that involve miR-17-5p, suggesting that miR-17-5p may be used as a marker of PD-L1 expression by metastatic lesions and ultimately a predictor of responses to BRAFi or MEKi
Inflammatory indexes as predictive factors for platinum sensitivity and as prognostic factors in recurrent epithelial ovarian cancer patients: a MITO24 retrospective study
Neutrophil-to-lymphocyte ratio (NLR) and systemic inflammatory index (SII) are prognostic factors in epithelial ovarian cancer (EOC). Their predictive value for platinum-sensitivity and their role in recurrent EOC are unknown. A total of 375 EOC patients were retrospectively analyzed. The correlation between baseline NLR and SII, and platinum-free interval (PFI) according to first line bevacizumab treatment were analyzed using logistic regression analyses adjusted for baseline patient characteristics. Subsequently NLR and SII calculated before second line treatment initiation were evaluated to identify a potential correlation with progression-free survival (PFS) and overall survival (OS) in platinum-sensitive and in platinum-resistant population. In multivariate analysis, NLR ≥ 3 is an independent predictive factor for PFI at 6 months in the chemotherapy group (OR = 2.77, 95% CI 1.38–5.56, p = 0.004), not in bevacizumab treated patients. After having adjusted for ECOG performance status, histology, ascites, bevacizumab treatment at second line and BRCA status, NLR ≥ 3 and SII ≥ 730 are significantly associated with worse OS in platinum-sensitive (HR = 2.69, 95% CI 1.60–4.53, p = 0.002; HR = 2.11, 95% CI 1.29–3.43, p = 0.003, respectively), not in platinum-resistant EOC patients. Low NLR is an independent predictive factor for platinum-sensitivity in patients treated without bevacizumab. NLR and SII are prognostic factors in recurrent platinum-sensitive EOC patients
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Distributed analysis with CRAB: The client-server architecture evolution and commissioning
CRAB (CMS Remote Analysis Builder) is the tool used by CMS to enable running physics analysis in a transparent manner over data distributed across many sites. It abstracts out the interaction with the underlying batch farms, grid infrastructure and CMS workload management tools, such that it is easily usable by non-experts. CRAB can be used as a direct interface to the computing system or can delegate the user task to a server. Major efforts have been dedicated to the client-server system development, allowing the user to deal only with a simple and intuitive interface and to delegate all the work to a server. The server takes care of handling the users jobs during the whole lifetime of the users task. In particular, it takes care of the data and resources discovery, process tracking and output handling. It also provides services such as automatic resubmission in case of failures, notification to the user of the task status, and automatic blacklisting of sites showing evident problems beyond what is provided by existing grid infrastructure. The CRAB Server architecture and its deployment will be presented, as well as the current status and future development. In addition the experience in using the system for initial detector commissioning activities and data analysis will be summarized
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