507 research outputs found

    Knowledge Gaps in the Fetal to Neonatal Transition of Infants With a Congenital Diaphragmatic Hernia

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    Clinical research for infants born with a congenital diaphragmatic hernia (CDH) has until recently mainly focused on advances in prenatal and postnatal treatment. However, during the early perinatal transition period there are major physiological adaptations. For most infants these changes will happen uneventfully, but for CDH infants this marks the beginning of serious respiratory complications. In recent years, there is emerging evidence that the clinical management during the perinatal stabilization period in the delivery room may influence postnatal outcomes. Herein, we discuss major knowledge gaps and novel concepts that aim to optimize fetal to neonatal transition for infants with CDH. One such novel and interesting approach is performing resuscitation with an intact umbilical cord, the efficacy of this procedure is currently being investigated in several clinical trials. Furthermore, close evaluation of neonatal physiological parameters in the first 24 h of life might provide early clues concerning the severity of lung hypoplasia and the risk of adverse outcomes. We will provide an overview of trending concepts and discuss potential areas for future research

    Real Time Turbulent Video Perfecting by Image Stabilization and Super-Resolution

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    Image and video quality in Long Range Observation Systems (LOROS) suffer from atmospheric turbulence that causes small neighbourhoods in image frames to chaotically move in different directions and substantially hampers visual analysis of such image and video sequences. The paper presents a real-time algorithm for perfecting turbulence degraded videos by means of stabilization and resolution enhancement. The latter is achieved by exploiting the turbulent motion. The algorithm involves generation of a reference frame and estimation, for each incoming video frame, of a local image displacement map with respect to the reference frame; segmentation of the displacement map into two classes: stationary and moving objects and resolution enhancement of stationary objects, while preserving real motion. Experiments with synthetic and real-life sequences have shown that the enhanced videos, generated in real time, exhibit substantially better resolution and complete stabilization for stationary objects while retaining real motion.Comment: Submitted to The Seventh IASTED International Conference on Visualization, Imaging, and Image Processing (VIIP 2007) August, 2007 Palma de Mallorca, Spai

    Charge and Isospin Fluctuations in High Energy pp-Collisions

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    Charge and isospin event-by-event fluctuations in high-energy pp-collisions are predicted within the Unitary Eikonal Model, in particular the fluctuation patterns of the ratios of charged-to-charged and neutral-to-charged pions. These fluctuations are found to be sensitive to the presence of unstable resonances, such as ρ\rho and ω\omega mesons. We predict that the charge-fluctuation observable DUEMD_{UEM} should be restricted to the interval 8/3≀DUEM≀48/3\le D_{UEM}\le 4 depending on the ρ/π\rho /\pi production ratio. Also, the isospin fluctuations of the DCC-type of the ratio of neutral-to-charged pions are suppressed if pions are produced together with ρ\rho mesons.Comment: Latex, 5 pages, no figures. To appear in the proceedings of 9th Adriatic Meeting, Dubrovnik, Croatia, 4 - 14 September 2003. Added reference into reference no.

    Vascular reactivity is altered in the placentas of fetuses with congenital diaphragmatic hernia

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    Introduction: Infants with congenital diaphragmatic hernia (CDH) often develop pulmonary hypertension but frequently fail to respond to vasodilator therapy, for instance because of an altered pulmonary vasoreactivity. Investigating such alterations in vivo is impossible. We hypothesised that these alterations are also present in fetoplacental vessels, since both vasculatures are exposed to the same circulating factors (e.g. endothelin-1) and respond similarly to certain stimuli (e.g. hypoxia). As proof-of-concept, we compared fetoplacental vasoreactivity between healthy and CDH-affected placentas. Methods: Fetoplacental vascular function of healthy and antenatally diagnosed left-sided CDH fetuses was assessed by wire myography. Placental expression of enzymes and receptors involved in the altered vasoreactive pathways was measured using quantitative PCR. Results: CDH arteries (n = 6) constricted more strongly to thromboxane A2 agonist U46619 (p &lt; 0.001) and dilated less to bradykinin (p = 0.01) and nitric oxide (NO)-donor sodium nitroprusside (p = 0.04) than healthy arteries (n = 8). Vasodilation to prostacyclin analogue iloprost and adenylate cyclase stimulator forskolin, and vasoconstriction to endothelin-1 were not different between both groups. Angiotensin II did not induce vasoconstriction. Phosphodiesterase inhibitors sildenafil and milrinone did not affect responses to sodium nitroprusside, forskolin, or U46619. The mRNA expression of guanylate cyclase 1 soluble subunit alpha 1 (p = 0.003) and protein kinase cyclic guanine monophosphate (cGMP)-dependent 1 (p = 0.02) were reduced in CDH versus healthy placentas. Discussion: The identified changes in the thromboxane and NO-cGMP pathways in the fetoplacental vasculature correspond with currently described alterations in the pulmonary vasculature in CDH. Therefore, fetoplacental arteries may provide an opportunity to predict pulmonary therapeutic responses in infants with CDH.</p

    Unital Quantum Channels - Convex Structure and Revivals of Birkhoff's Theorem

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    The set of doubly-stochastic quantum channels and its subset of mixtures of unitaries are investigated. We provide a detailed analysis of their structure together with computable criteria for the separation of the two sets. When applied to O(d)-covariant channels this leads to a complete characterization and reveals a remarkable feature: instances of channels which are not in the convex hull of unitaries can return to it when either taking finitely many copies of them or supplementing with a completely depolarizing channel. In these scenarios this implies that a channel whose noise initially resists any environment-assisted attempt of correction can become perfectly correctable.Comment: 31 page

    Physiological-based cord clamping versus immediate cord clamping for infants born with a congenital diaphragmatic hernia (PinC):study protocol for a multicentre, randomised controlled trial

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    Introduction Pulmonary hypertension is a majordeterminant of postnatal survival in infants with acongenital diaphragmatic hernia (CDH). The current careduring the perinatal stabilisation period in these infantsmight contribute to the development of pulmonaryhypertension after birth—in particular umbilical cordclamping before lung aeration. An ovine model ofdiaphragmatic hernia demonstrated that cord clampingafter lung aeration, called physiological-based cordclamping (PBCC), avoided the initial high pressures in thelung vasculature while maintaining adequate blood flow,thereby avoiding vascular remodelling and aggravationof pulmonary hypertension. We aim to investigate if theimplementation of PBCC in the perinatal stabilisation periodof infants born with a CDH could reduce the incidence ofpulmonary hypertension in the first 24 hours after birth.Methods and analysis We will perform a multicentre,randomised controlled trial in infants with an isolatedleft-sided CDH, born at ≄35.0 weeks. Before birth, infantswill be randomised to either PBCC or immediate cordclamping, stratified by treatment centre and severity ofpulmonary hypoplasia on antenatal ultrasound. PBCCwill be performed using a purpose- built resuscitationtrolley. Cord clamping will be performed when the infantis considered respiratory stable, defined as a heartrate &gt;100 bpm, preductal oxygen saturation &gt;85%,while using a fraction of inspired oxygen of &lt;0.5. Theprimary outcome is pulmonary hypertension diagnosedin the first 24 hours after birth, based on clinical andechocardiographic parameters. Secondary outcomesinclude neonatal as well as maternal outcomes.Ethics and dissemination Central ethical approvalwas obtained from the Medical Ethical Committee ofthe Erasmus MC, Rotterdam, The Netherlands (METC2019-0414). Local ethical approval will be obtained bysubmitting the protocol to the regulatory bodies and localinstitutional review boards

    NP-hardness of Deciding Convexity of Quartic Polynomials and Related Problems

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    We show that unless P=NP, there exists no polynomial time (or even pseudo-polynomial time) algorithm that can decide whether a multivariate polynomial of degree four (or higher even degree) is globally convex. This solves a problem that has been open since 1992 when N. Z. Shor asked for the complexity of deciding convexity for quartic polynomials. We also prove that deciding strict convexity, strong convexity, quasiconvexity, and pseudoconvexity of polynomials of even degree four or higher is strongly NP-hard. By contrast, we show that quasiconvexity and pseudoconvexity of odd degree polynomials can be decided in polynomial time.Comment: 20 page

    Heavy quarkonium: progress, puzzles, and opportunities

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    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the BB-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair
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