Delay-induced Synchronization Phenomena in an Array of Globally Coupled Logistic Maps

We study the synchronization of a linear array of globally coupled identical logistic maps. We consider a time-delayed coupling that takes into account the finite velocity of propagation of the interactions. We find globally synchronized states in which the elements of the array evolve along a periodic orbit of the uncoupled map, while the spatial correlation along the array is such that an individual map sees all other maps in his present, current, state. For values of the nonlinear parameter such that the uncoupled maps are chaotic, time-delayed mutual coupling suppress the chaotic behavior by stabilizing a periodic orbit which is unstable for the uncoupled maps. The stability analysis of the synchronized state allows us to calculate the range of the coupling strength in which global synchronization can be obtained.Comment: 8 pages, 7 figures, changed content, added reference

m(b)(m(z)) from jet production at the Z peak in the Cambridge algorithm

We consider the production of heavy quark jets at the Z-pole at the next-to-leading order (NLO) using the {\it Cambridge jet-algorithm}. We study the effects of the quark mass in two- and three-jet observables and the uncertainty due to unknown higher order corrections as well as due to fragmentation. We found that the three-jet observable has remarkably small NLO corrections, which are stable with respect to the change of the renormalization scale, when expressed in terms of the {\it running quark mass} at the mZ-scale. The size of the hadronization uncertainty for this observable remains reasonably small and is very stable with respect to changes in the jet resolution parameter yc

Relation between Epidural Analgesia and severe perineal laceration in childbearing women in Catalonia

Our objectives were to study the association between epidural analgesia and risk of severe perineal laceration (SPL), and identify additional risk factors for SPL. This multicentre study consisted of an analysis of data from the MidconBirth Phase I Database, on the use of EA and perineal results during childbirth. (World Health Organization, International Clinical Trials Registry Platform, 2016: http://apps.who.int/trialsearch/Trial2.aspx?TrialID=ISRCTN17833269). We conducted a prospective study of pregnant women at term between July 2016 and July 2017 in 30 public maternity hospitals in Catalonia, Spain. Inclusion criteria were an uncomplicated singleton pregnancy, in cephalic presentation and vaginal birth. Data was analysed separately for instrumental births and spontaneous vaginal births, as the former is more frequently associated with episiotomy and more perineal lacerations. Risk factors as well as protective factors in each cohort of women (instrumental and spontaneous vaginal birth), were identified. Multivariate logistic regression model was performed to study the association between epidural analgesia and SPL to identify potential confounders. Odds ratios (OR), using 95% confidence intervals (CI) were constructed. During the study period, 5497 eligible women gave birth, 77.46% of them received epidural analgesia. SPL occurred in 1.63% of births. The univariate analysis showed births with epidural analgesia had significantly higher rates of inductions, augmentation of labour, lithotomy position for birth and episiotomy. However, this association disappeared when the variable "type of vaginal birth" was introduced. In multivariate logistic regression, nulliparity was the major predictor for SPL (OR: 0.17; CI 95%: 0.08-0.34, p: 0.000). Epidural analgesia was not associated with SPL once confounding factors were included. Other interesting factors associated with SPL were identified. This paper identifies important practice areas which contribute to SPL and which have the potential to be rectified. It offers evidence on the role that EA plays on pelvic floor injuries and it adds to existing evidence about the disadvantages of using the lithotomy position for birth, especially in relation to SPL. It highlights the need for practice change in Catalonia from what can be considered a medical model of care to one more aligned with the midwifery philosophy of care through the development of clinical guidelines. It also signals the need to provide women with evidence base upon which to make informed choices on the use of EA, specifically in relation to SPL. [Abstract copyright: Copyright © 2018 Elsevier Ltd. All rights reserved.

Radio emission and jets from microquasars

To some extent, all Galactic binary systems hosting a compact object are potential `microquasars', so much as all galactic nuclei may have been quasars, once upon a time. The necessary ingredients for a compact object of stellar mass to qualify as a microquasar seem to be: accretion, rotation and magnetic field. The presence of a black hole may help, but is not strictly required, since neutron star X-ray binaries and dwarf novae can be powerful jet sources as well. The above issues are broadly discussed throughout this Chapter, with a a rather trivial question in mind: why do we care? In other words: are jets a negligible phenomenon in terms of accretion power, or do they contribute significantly to dissipating gravitational potential energy? How do they influence their surroundings? The latter point is especially relevant in a broader context, as there is mounting evidence that outflows powered by super-massive black holes in external galaxies may play a crucial role in regulating the evolution of cosmic structures. Microquasars can also be thought of as a form of quasars for the impatient: what makes them appealing, despite their low number statistics with respect to quasars, are the fast variability time-scales. In the first approximation, the physics of the jet-accretion coupling in the innermost regions should be set by the mass/size of the accretor: stellar mass objects vary on 10^5-10^8 times shorter time-scales, making it possible to study variable accretion modes and related ejection phenomena over average Ph.D. time-scales. [Abridged]Comment: 28 pages, 13 figures, To appear in Belloni, T. (ed.): The Jet Paradigm - From Microquasars to Quasars, Lect. Notes Phys. 794 (2009

Tracing jet emission at the base of a high-mass YSO: First AMBER/VLTI observations of the Brγ emission in IRAS 13481-6124

Aims. To probe the circumstellar environment of IRAS 13481-6124, a 20 M⊙ high-mass young stellar object (HMYSO) with a collimated parsec-scale jet and an accretion disc, we investigate the origin of its Brγ emission line through near-infrared (NIR) interferometry. Methods. We present the first AMBER/VLTI observations of the Brγ emitting region in an HMYSO at medium spectral resolution (R = 1500). Results. Our AMBER/VLTI observations reveal a spatially and spectrally resolved Brγ line in emission with a strong P Cygni profile, indicating outflowing matter with a terminal velocity of ∼500 km s-1. Visibilities, differential phases, and closure phases are detected in our observations within the spectral line and in the adjacent continuum. Both total visibilities (continuum plus line emitting region) and pure-line visibilities indicate that the Brγ-emitting region is more compact (2-4 mas in diameter or ∼6-13 au at 3.2 kpc) than the continuum-emitting region (∼5.4 mas or ∼17 au). The absorption feature is also spatially resolved at the longest baselines (81 and 85 m) and has a visibility that is slightly smaller than the continuum-emitting region. The differential phases at the four longest baselines display an "S"-shaped structure across the line, peaking in the blue- and red-shifted high-velocity components. The calibrated photocentre shifts are aligned with the known jet axis, i.e they are probably tracing an ionised jet. The high-velocity components (vr ∼ 100-500 km s-1) are located far from the source, whereas the low-velocity components (0-100 km s-1) are observed to be closer, indicating a strong acceleration of the gas flow in the inner 10 au. Finally, a non-zero closure phase along the continuum is detected. By comparing our observations with the synthetic images of the continuum around 2.16 μm, we confirm that this feature originates from the asymmetric brightness distribution of the continuum owing to the inclination of the inner disc

Doppler ultrasound in the measurement of pulse wave velocity: agreement with the Complior method

Aortic stiffness is an independent predictor factor for cardiovascular risk. Different methods for determining pulse wave velocity (PWV) are used, among which the most common are mechanical methods such as SphygmoCor or Complior, which require specific devices and are limited by technical difficulty in obtaining measurements. Doppler guided by 2D ultrasound is a good alternative to these methods. We studied 40 patients (29 male, aged 21 to 82 years) comparing the Complior method with Doppler. Agreement of both devices was high (R = 0.91, 0.84-0.95, 95% CI). The reproducibility analysis revealed no intra-nor interobserver differences. Based on these results, we conclude that Doppler ultrasound is a reliable and reproducible alternative to other established methods for the measurement of aortic PWV

Effect of combined β-Lactam/Macrolide therapy on mortality according to the microbial etiology and inflammatory status of patients with community-acquired pneumonia

Antibiotic combinations that include macrolides have shown lower mortality rates than β-lactams in monotherapy or combined with fluoroquinolones in patients with community-acquired pneumonia (CAP). However, this effect has not been studied according to the levels of C-reactive protein in CAP with identified microbial cause. In patients with CAP and known microbial cause we aimed to evaluate 30-day mortality of a β-lactam plus macrolide (BL + M) compared with a fluoroquinolone alone or with a β-lactam (FQ ± BL). METHODS: We analyzed a prospective observational cohort of patients with CAP admitted to the Hospital Clinic of Barcelona between 1996 and 2016. We included only patients with known microbial cause. RESULTS: Of 1,715 patients (29%) with known etiology, a total of 932 patients (54%) received BL + M. Despite lower crude mortality in the BL + M group in the overall population (BL + M, 5% vs FQ ± BL, 8%; P = .015), after adjustment by a propensity score and baseline characteristics, the combination of BL + M had a protective effect on mortality only in patients with high inflammatory response (C-reactive protein, > 15 mg/dL) and pneumococcal CAP (adjusted OR, 0.28; 95% CI, 0.09-0.93). No benefits on mortality were observed for the population without high inflammatory response and pneumococcal CAP or with other etiologies. CONCLUSIONS: The combination of a β-lactam with a macrolide was associated with decreased mortality in patients with pneumococcal CAP and in patients with high systemic inflammatory response. When both factors occurred together, BL + M was protective for mortality in the multivariate analysis

MRI Discriminates Thrombus Composition and ST Resolution after Percutaneous Coronary Intervention in Patients with ST-Elevation Myocardial Infarction

Histological composition of material obtained by thrombus aspiration during percutaneous coronary intervention (PCI) in patients with ST-segment elevation acute myocardial infarction (STEMI) is highly variable. We aimed to characterize this material using magnetic resonance imaging (MRI) and to correlate MRI findings with the success of PCI in terms of ST-segment resolution. Thrombus aspiration during primary or rescue PCI was attempted in 100 consecutive STEMI patients, of whom enough material for MRI was obtained in 59. MR images were obtained at 9.4T and T1 and T2 values were measured. Patients with (n = 31) and without (n = 28) adequate ST resolution 120 min after PCI (≥70% of pre-PCI value) had similar baseline characteristics except for a higher prevalence of diabetes mellitus in the latter (10 vs. 43%, p = 0.003). T1 values were similar in both groups (1248±112 vs. 1307±85 ms, respectively, p = 0.7). T2 values averaged 31.2±10.3 and 36.6±12.2 ms; in thrombus from patients with and without adequate ST resolution (p = 0.09). After adjusting for diabetes and other baseline characteristics, lower T2 values were significantly associated with inadequate ST resolution (odds ratio for 1 ms increase 1.08, CI 95% 1.01–1.16, p = 0.027). Histology classified thrombus in 3 groups: coagulated blood (n = 38), fibrin rich (n = 9) and lipid-rich (n = 3). Thrombi composed mostly of coagulated blood were characterized as being of short (n = 10), intermediate (n = 15) or long evolution (n = 13), T2 values being 34.0±13.2, 31.9±8.3 and 31.5±7.9 ms respectively (p = NS). In this subgroup, T2 was significantly higher in specimens from patients with inadequate perfusion (35.9±10.3 versus 28.6±6.7 ms, p = 0.02). This can be of clinical interest as it provides information on the probability of adequate ST resolution, a surrogate for effective myocardial reperfusion

Furiously fast and red: sub-second optical flaring in V404 Cyg during the 2015 outburst peak

We present observations of rapid (sub-second) optical flux variability in V404 Cyg during its 2015 June outburst. Simultaneous three-band observations with the ULTRACAM fast imager on four nights show steep power spectra dominated by slow variations on ∼100–1000 s time-scales. Near the peak of the outburst on June 26, a dramatic change occurs and additional, persistent sub-second optical flaring appears close in time to giant radio and X-ray flaring. The flares reach peak optical luminosities of ∼ few × 1036 erg s−1. Some are unresolved down to a time resolution of 24 ms. Whereas the fast flares are stronger in the red, the slow variations are bluer when brighter. The redder slopes, emitted power and characteristic time-scales of the fast flares can be explained as optically thin synchrotron emission from a compact jet arising on size scales ∼140–500 Gravitational radii (with a possible additional contribution by a thermal particle distribution). The origin of the slower variations is unclear. The optical continuum spectral slopes are strongly affected by dereddening uncertainties and contamination by strong Hα emission, but the variations of these slopes follow relatively stable loci as a function of flux. Cross-correlating the slow variations between the different bands shows asymmetries on all nights consistent with a small red skew (i.e. red lag). X-ray reprocessing and non-thermal emission could both contribute to these. These data reveal a complex mix of components over five decades in time-scale during the outburst

First-line treatment in lymphomatoid papulosis: a retrospective multicentre study

Background: Data regarding response to treatment in lymphomatoid papulosis (LyP) are scarce. Aim: To assess the daily clinical practice approach to LyP and the response to first-line treatments. Methods: This was a retrospective study enrolling 252 patients with LyP. Results: Topical steroids, methotrexate and phototherapy were the most common first-line treatments, prescribed for 35%, 20% and 14% of the patients, respectively. Complete response (CR) was achieved in 48% of treated patients. Eczematous lesions significantly increased relative risk (RR) of not achieving CR (RR = 1.76; 95% CI 1.16-2.11). Overall median time to CR was 10 months (95% CI 6-13 months), and 78% of complete responders showed cutaneous relapse; both results were similar for all treatment groups (P > 0.05). Overall estimated median disease-free survival (DFS) was 11 months (95% CI 9-13 months) but DFS for patients treated with phototherapy was 23 months (95% CI 10-36 months; P < 0.03). Having the Type A LyP variant (RR = 2.04; 95% CI 0.96-4.30) and receiving a first-line treatment other than phototherapy (RR = 5.33; 95% CI 0.84-33.89) were significantly associated with cutaneous early relapse. Of the 252 patients, 31 (13%) had associated mycosis fungoides unrelated to therapeutic approach, type of LyP or T-cell receptor clonality. Conclusions: Current epidemiological, clinical and pathological data support previous results. Topical steroids, phototherapy and methotrexate are the most frequently prescribed first-line treatments. Although CR and cutaneous relapse rates do not differ between them, phototherapy achieves a longer DFS. Presence of Type A LyP and use of topical steroid or methotrexate were associated with an increased risk of early relapse