462 research outputs found
On stochastic sea of the standard map
Consider a generic one-parameter unfolding of a homoclinic tangency of an
area preserving surface diffeomorphism. We show that for many parameters
(residual subset in an open set approaching the critical value) the
corresponding diffeomorphism has a transitive invariant set of full
Hausdorff dimension. The set is a topological limit of hyperbolic sets
and is accumulated by elliptic islands.
As an application we prove that stochastic sea of the standard map has full
Hausdorff dimension for sufficiently large topologically generic parameters.Comment: 36 pages, 5 figure
IRS2 silencing increases apoptosis and potentiates the effects of ruxolitinib in jak2v617f-positive myeloproliferative neoplasms
Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)The recurrent V617F mutation in JAK2 (JAK2(V617F)) has emerged as the primary contributor to the pathogenesis of myeloproliferative neoplasms (MPN). However, the lack of complete response in most patients treated with the JAK1/2 inhibitor, ruxolitinib, indicates the need for identifying pathways that cooperate with JAK2. Activated JAK2 was found to be associated with the insulin receptor substrate 2 (IRS2) in non-hematological cells. We identified JAK2/IRS2 binding in JAK2(V617F) HEL cells, but not in the JAK2(WT) U937 cell line. In HEL cells, IRS2 silencing decreased STAT5 phosphorylation, reduced cell viability and increased apoptosis; these effects were enhanced when IRS2 silencing was combined with ruxolitinib. In U937 cells, IRS2 silencing neither reduced cell viability nor induced apoptosis. IRS1/2 pharmacological inhibition in primary MPN samples reduced cell viability in JAK2(V617F)-positive but not JAK2(WT) specimens; combination with ruxolitinib had additive effects. IRS2 expression was significantly higher in CD34(+) cells from essential thrombocythemia patients compared to healthy donors, and in JAK2(V617F) MPN patients when compared to JAK2(WT). Our data indicate that IRS2 is a binding partner of JAK2(V617F) in MPN. IRS2 contributes to increased cell viability and reduced apoptosis in JAK2-mutated cells. Combined pharmacological inhibition of IRS2 and JAK2 may have a potential clinical application in MPN.The recurrent V617F mutation in JAK2 (JAK2V617F) has emerged as the primary contributor to the pathogenesis of myeloproliferative neoplasms (MPN). However, the lack of complete response in most patients treated with the JAK1/2 inhibitor, ruxolitinib, indi7669486959sem informaçãoConselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)sem informaçã
The Cloud Factory II: gravoturbulent kinematics of resolved molecular clouds in a galactic potential
Interstellar matter and star formatio
Spatial rigid-multi-body systems with lubricated spherical clearance joints : modeling and simulation
The dynamic modeling and simulation of spatial rigid-multi-body systems with lubricated spherical joints is the main purpose of the present work. This issue is of paramount importance in the analysis and design of realistic multibody mechanical systems undergoing spatial motion. When the spherical clearance joint is modeled as dry contact; i.e., when there is no lubricant between the mechanical elements which constitute the joint, a body-to-body (typically metal-to-metal) contact takes place. The joint reaction forces in this case are evaluated through a Hertzian-based contact law. A hysteretic damping factor is included in the dry contact force model to account for the energy dissipation during the contact process. The presence of a fluid lubricant avoids the direct metal-to-metal contact. In this situation, the squeeze film action, due to the relative approaching motion between the mechanical joint elements, is considered utilizing the lubrication theory associated with the spherical bearings. In both cases, the intra-joint reaction forces are evaluated as functions of the geometrical, kinematical and physical characteristics of the spherical joint. These forces are then incorporated into a standard formulation of the systemâs governing equations of motion as generalized external forces. A spatial four bar mechanism that includes a spherical clearance joint is considered here as example. The computational simulations are carried out with and without the fluid lubricant, and the results are compared with those obtained when the system is modeled with perfect joints only. From the general results it is observed that the systemâs performance with lubricant effect presents fewer peaks in the kinematic and dynamic outputs, when compared with those from the dry contact joint model.Fundação para a CiĂŞncia e a Tecnologia (FCT
Extratores de cåpsulas porosas para o monitoramento da condutividade elÊtrica e do teor de potåssio na solução de um solo
Effects Of Therapeutic Approach On The Neonatal Evolution Of Very Low Birth Weight Infants With Patent Ductus Arteriosus
Objective To analyze the effects of treatment approach on the outcomes of newborns (birth weight [BW] < 1,000 g) with patent ductus arteriosus (PDA), from the Brazilian Neonatal Research Network (BNRN) on: death, bronchopulmonary dysplasia (BPD), severe intraventricular hemorrhage (IVH III/IV), retinopathy of prematurity requiring surgical (ROPsur), necrotizing enterocolitis requiring surgery (NECsur), and death/BPD.Methods This was a multicentric, cohort study, retrospective data collection, including newborns (BW < 1000 g) with gestational age (GA) < 33 weeks and echocardiographic diagnosis of PDA, from 16 neonatal units of the BNRN from January 1, 2010 to Dec 31, 2011. Newborns who died or were transferred until the third day of life, and those with presence of congenital malformation or infection were excluded. Groups: G1 - conservative approach (without treatment), G2 - pharmacologic (indomethacin or ibuprofen), G3 - surgical ligation (independent of previous treatment). Factors analyzed: antenatal corticosteroid, cesarean section, BW, GA, 5 min. Apgar score < 4, male gender, Score for Neonatal Acute Physiology Perinatal Extension (SNAPPE II), respiratory distress syndrome (RDS), late sepsis (LS), mechanical ventilation (MV), surfactant (< 2 h of life), and time of MV. Outcomes: death, O2 dependence at 36 weeks (BPD36wks), IVH III/IV, ROPsur, NECsur, and death/BPD36wks. Statistics: Student's t-test, chi-squared test, or Fisher's exact test; Odds ratio (95% CI); logistic binary regression and backward stepwise multiple regression. Software: MedCalc (Medical Calculator) software, version 12.1.4.0. p-values < 0.05 were considered statistically significantResults 1,097 newborns were selected and 494 newborns were included: G1 - 187 (37.8%), G2 - 205 (41.5%), and G3 - 102 (20.6%). The highest mortality was observed in G1 (51.3%) and the lowest in G3 (14.7%). The highest frequencies of BPD36wks (70.6%) and ROPsur were observed in G3 (23.5%). The lowest occurrence of death/BPD36wks occurred in G2 (58.0%). Pharmacological (OR 0.29; 95% CI: 0.14-0.62) and conservative (OR 0.34; 95% CI: 0.14-0.79) treatments were protective for the outcome death/BPD36wks. Conclusion The conservative approach of PDA was associated to high mortality, the surgical approach to the occurrence of BPD36wks and ROPsur, and the pharmacological treatment was protective for the outcome death/BPD36wks.906616623Clyman, R.I., Mechanisms regulating the ductus arteriosus (2006) Biol Neonate., 89, pp. 330-335Benitz, W.E., Treatment of persistent patent ductus arteriosus in preterm infants: Time to accept the null hypothesis? (2010) J Perinatol., 30, pp. 241-252Redline, R.W., Wilson-Costello, D., Hack, M., Placental and other perinatal risk factors for chronic lung disease in very low birth weight infants (2002) Pediatr Res., 52, pp. 713-719Evans, N., Kluckow, M., Early ductal shunting and intraventricular haemorrhage in ventilated preterm infants (1996) Arch Dis Child Fetal Neonatal Ed., 75, pp. 183-F186Noerr, B., Current controversies in the understanding of necrotizing enterocolitis Part 1 (2003) Adv Neonatal Care., 3, pp. 107-120Koch, J., Hensley, G., Roy, L., Brown, S., Ramaciotti, C., Rosenfeld, C.R., Prevalence of spontaneous closure of the ductus arteriosus in neonates at a birth weight of 1000 grams or less (2006) Pediatrics., 117, pp. 1113-1121Afiune, J.Y., Singer, J.M., Leone, C.R., Evolução ecocardiogråfica de recÊm-nascidos com persistência do canal arterial (2005) J Pediatr (Rio J)., 81, pp. 454-460Sosenko, I.R., Fajardo, M.F., Claure, N., Bancalari, E., Timing of patent ductus arteriosus treatment and respiratory outcome in premature infants: A double-blind randomized controlled trial (2012) J Pediatr., 160, pp. 929-935. , e1Laughon, M.M., Simmons, M.A., Bose, C.L., Patency of the ductus arteriosus in the premature infant: Is it pathologic? Should it be treated? (2004) Curr Opin Pediatr., 16, pp. 146-151Clyman, R.I., Chorne, N., Patent ductus arteriosus: Evidence for and against treatment (2007) J Pediatr., 150, pp. 216-219Bose, C.L., Laughon, M., Treatment to prevent patency of the ductus arteriosus: Beneficial or harmful? (2006) J Pediatr., 148, pp. 713-714Clyman, R.I., Couto, J., Murphy, G.M., Patent ductus arteriosus: Are current neonatal treatment options better or worse than no treatment at all? (2012) Semin Perinatol., 36, pp. 123-129Alexander, G.R., Himes, J.H., Kaufman, R.B., Mor, J., Kogan, M., A United States national reference for fetal growth (1996) Obstet Gynecol., 87, pp. 163-168Jhaveri, N., Moon-Grady, A., Clyman, R.I., Early surgical ligation versus a conservative approach for management of patent ductus arteriosus that fails to close after indomethacin treatment (2010) J Pediatr., 157. , 381-7, 387.e1Clyman, R., Cassady, G., Kirklin, J.K., Collins, M., Philips, J.B., III, The role of patent ductus arteriosus ligation in bronchopulmonary dysplasia: Reexamining a randomized controlled trial (2009) J Pediatr., 154, pp. 873-876Mirea, L., Sankaran, K., Seshia, M., Ohlsson, A., Allen, A.C., Aziz, K., Treatment of patent ductus arteriosus and neonatal mortality/morbidities: Adjustment for treatment selection bias (2012) J Pediatr., 161, pp. 689-694. , e1Youn, Y., Lee, J.Y., Lee, J.H., Kim, S.Y., Sung, I.K., Lee, J.Y., Impact of patient selection on outcomes of PDA in very low birth weight infants (2013) Early Hum Dev., 89, pp. 175-17
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV
The Lambda(b) differential production cross section and the cross section
ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum
pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7
TeV using data collected by the CMS experiment at the LHC. The measurements are
based on Lambda(b) decays reconstructed in the exclusive final state J/Psi
Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and
Lambda to proton pion, using a data sample corresponding to an integrated
luminosity of 1.9 inverse femtobarns. The product of the cross section times
the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls
faster than that of b mesons. The measured value of the cross section times the
branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06
+/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for
anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are
statistical and systematic, respectively.Comment: Submitted to Physics Letters
Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV
A search is presented for physics beyond the standard model (BSM) in final
states with a pair of opposite-sign isolated leptons accompanied by jets and
missing transverse energy. The search uses LHC data recorded at a
center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to
an integrated luminosity of approximately 5 inverse femtobarns. Two
complementary search strategies are employed. The first probes models with a
specific dilepton production mechanism that leads to a characteristic kinematic
edge in the dilepton mass distribution. The second strategy probes models of
dilepton production with heavy, colored objects that decay to final states
including invisible particles, leading to very large hadronic activity and
missing transverse energy. No evidence for an event yield in excess of the
standard model expectations is found. Upper limits on the BSM contributions to
the signal regions are deduced from the results, which are used to exclude a
region of the parameter space of the constrained minimal supersymmetric
extension of the standard model. Additional information related to detector
efficiencies and response is provided to allow testing specific models of BSM
physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO
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