Stability Properties of Nonhyperbolic Chaotic Attractors under Noise

We study local and global stability of nonhyperbolic chaotic attractors contaminated by noise. The former is given by the maximum distance of a noisy trajectory from the noisefree attractor, while the latter is provided by the minimal escape energy necessary to leave the basin of attraction, calculated with the Hamiltonian theory of large fluctuations. We establish the important and counterintuitive result that both concepts may be opposed to each other. Even when one attractor is globally more stable than another one, it can be locally less stable. Our results are exemplified with the Holmes map, for two different sets of parameter, and with a juxtaposition of the Holmes and the Ikeda maps. Finally, the experimental relevance of these findings is pointed out.Comment: Phys.Rev. Lett., to be publishe

Escaping from nonhyperbolic chaotic attractors

We study the noise-induced escape process from chaotic attractors in nonhyperbolic systems. We provide a general mechanism of escape in the low noise limit, employing the theory of large fluctuations. Specifically, this is achieved by solving the variational equations of the auxiliary Hamiltonian system and by incorporating the initial conditions on the chaotic attractor unambiguously. Our results are exemplified with the H{\'e}non and the Ikeda map and can be implemented straightforwardly to experimental data.Comment: replaced with published versio

Hepatitis B testing and treatment in HIV patients in The Gambia - compliance with international guidelines and clinical outcomes

Background Compliance with WHO guidelines on HBV screening and treatment in HIV-coinfected patients is often challenging in resource limited countries and has been poorly assessed in sub-Saharan Africa. Methods Between 2015 and 2016, we assessed physician’s compliance with WHO guidelines on HIV-HBV coinfection in the largest HIV clinic in The Gambia, and the hepatic outcomes in HIV-HBV coinfected patients as compared to randomly selected HIV-monoinfected controls. Results 870 HIV-infected patients regularly seen in this clinic agreed to participate in our study. Only 187 (21.5%, 95% CI 18.8–24.3) had previously been screened for HBsAg, 23 (12.3%, 95% CI 8.0–17.9) were positive of whom none had liver assessment and only 6 (26.1%) had received Tenofovir. Our HBV testing intervention was accepted by all participants and found 94/870 (10.8%, 95% CI 8.8–13.1) positive, 78 of whom underwent full liver assessment along with 40 HBsAg-negative controls. At the time of liver assessment, 61/78 (78.2%) HIV-HBV coinfected patients received ART with 7 (11.5%) on Tenofovir and 54 (88.5%) on Lamivudine alone. HIV-HBV coinfected patients had higher APRI score compared to controls (0.58 vs 0.42, p = 0.002). HBV DNA was detectable in 52/53 (98.1%) coinfected patients with 14/53 (26.4%) having HBV DNA >20,000 IU/L. 10/12 (83.3%) had at least one detectable 3TC-associated HBV resistance, which tended to be associated with increase in liver fibrosis after adjusting for age and sex (p = 0.05). Conclusions Compliance with HBV testing and treatment guidelines is poor in this Gambian HIV programme putting coinfected patients at risk of liver complications. However, the excellent uptake of HBV screening and linkage to care in our study suggests feasible improvements

Sucrose effect on broomrape (Orobanche crenata) development on narbon bean (Vicia narbonensis L.)

The growth and development of broomrapes (Orobanche spp.) fully depends on the nutritional connection established between the parasitic plant and the root of the corresponding host plant. In thepresent study, narbon bean plants infected with Orobanche crenata were watered with different concentrations of sucrose (0.014, 0.044, 0.088 and 0.146 M) in order to evaluate its effect on the earlygrowth stages of the parasite. The germination of O. crenata seeds decreased with increasing sucrose concentrations and the number of infection attachments of crenata broomrapes decreased significantlywhen sucrose was present. A parallel experiment was conducted with identical sorbitol concentrations in order to determinate the role of the osmotic potential in the inhibition of the parasite growth. Ourresults showed that while low sucrose concentrations significantly reduced seed germination in O. crenata, similar concentrations of sorbitol have no significant effect thus indicating that the effect ofsucrose is not simply osmotic. Sucrose phytotoxicity was also studied by considering the dry weight of the host plants

Psychometric properties and validation of the Spanish versions of the overall anxiety and depression severity and impairment scales

Background: Anxiety and depressive disorders are the most frequent disorders for which patients seek care in public health settings in Spain. This study aimed at validating the Overall Anxiety Severity and Impairment Scale (OASIS) and the Overall Depression Severity and Impairment Scale (ODSIS), which are brief screening scales for anxiety and depression consisting of only five items each. Methods: The study was conducted in a Spanish clinical sample receiving outpatient mental health treatment (N = 339). A subsample of participants (n = 219) was assessed before and after receiving a course of cognitive-behavioral treatment. Results: The results revealed excellent internal consistency estimates (Cronbach's alpha for the OASIS and the ODSIS was 0.87 and 0.94, respectively), along with promising convergent and discriminant validity and test-criterion relationships (i.e., moderate correlation with other measures of depression and anxiety, as well as with neuroticism, quality of life, adjustment, and negative affect). A one-dimensional structure was obtained for the OASIS and the ODSIS. The ROC analyses indicated an area under the curve of 0.83 for the OASIS and the ODSIS when predicting moderate-to-severe anxiety and depression, respectively. Good sensitivity to therapeutic change was also evidence and the analysis of the sensitivity as a function of 1-specificity area suggested a cutoff value of 10 for both scales. Limitations: Inter-rater reliability of diagnoses with the ADIS-IV interview could not be investigated and the results obtained may not be generalizable to other samples and health settings. Conclusions: The availability of these two short and psychometrically sound measures should make screening of anxiety and depressive symptoms in routine care more feasible

Psychometric properties and validation of the Spanish versions of the overall anxiety and depression severity and impairment scales

Background Anxiety and depressive disorders are the most frequent disorders for which patients seek care in public health settings in Spain. This study aimed at validating the Overall Anxiety Severity and Impairment Scale (OASIS) and the Overall Depression Severity and Impairment Scale (ODSIS), which are brief screening scales for anxiety and depression consisting of only five items each. Methods The study was conducted in a Spanish clinical sample receiving outpatient mental health treatment (N = 339). A subsample of participants (n = 219) was assessed before and after receiving a course of cognitive-behavioral treatment. Results The results revealed excellent internal consistency estimates (Cronbach's alpha for the OASIS and the ODSIS was 0.87 and 0.94, respectively), along with promising convergent and discriminant validity and test-criterion relationships (i.e., moderate correlation with other measures of depression and anxiety, as well as with neuroticism, quality of life, adjustment, and negative affect). A one-dimensional structure was obtained for the OASIS and the ODSIS. The ROC analyses indicated an area under the curve of 0.83 for the OASIS and the ODSIS when predicting moderate-to-severe anxiety and depression, respectively. Good sensitivity to therapeutic change was also evidence and the analysis of the sensitivity as a function of 1-specificity area suggested a cutoff value of 10 for both scales. Limitations Inter-rater reliability of diagnoses with the ADIS-IV interview could not be investigated and the results obtained may not be generalizable to other samples and health settings. Conclusions The availability of these two short and psychometrically sound measures should make screening of anxiety and depressive symptoms in routine care more feasible

Recursos de osteosíntesis en fémur porótico.

Objetivos. Exponer dos técnicas quirúrgicas de refuerzo de una osteosíntesis convencional en situaciones especiales de debilidad ósea del fémur, como son las fracturas periprotésicas, las fracturas patológicas y los fracasos de osteosíntesis previas en pacientes de edad avanzada. La debilidad del hueso puede llegar a dificultar la realización de osteosíntesis estables en fracturas de fémur porque impide el correcto anclaje del material, ya sean agujas, cerclajes o especialmente tornillos. Material y método. Se evaluaron 13 pacientes (media de edad de 78,3 años), 9 de los cuales sufrieron fracturas periprotésicas de fémur, dos fracasos de osteosíntesis previas, un caso de pseudoartrosis tras una fractura periprotésica y una fractura diafisaria en un fémur muy osteoporótico, en los cuales se han utilizado dos técnicas de refuerzo del hueso: el cementado endomedular y el implante de contraplacas atornilladas de aloinjerto óseo congelado. Resultados. Se realizó un seguimiento de estos pacientes en un período que oscila entre 12 y 72 meses (media de 26,2 meses). En un caso se produjo una pseudoartrosis de la fractura por ocupación accidental del foco de fractura por el cemento acrílico. En los 12 casos restantes se consiguió la consolidación. Conclusiones. El cementado endomedular y la utilización de contraplacas atornilladas de aloinjerto óseo son dos recursos técnicos útiles en situaciones especiales en las que es necesario realizar una osteosíntesis estable sobre un hueso muy débil

Enhancement of Noise-induced Escape through the Existence of a Chaotic Saddle

We study the noise-induced escape process in a prototype dissipative nonequilibrium system, the Ikeda map. In the presence of a chaotic saddle embedded in the basin of attraction of the metastable state, we find the novel phenomenon of a strong enhancement of noise-induced escape. This result is established by employing the theory of quasipotentials. Our finding is of general validity and should be experimentally observable.Comment: 4 page

The second data release of the INT Photometric Ha Survey of the Northern Galactic Plane (IPHAS DR2)

The INT/WFC Photometric Hα Survey of the Northern Galactic Plane (IPHAS) is a 1800 deg2 imaging survey covering Galactic latitudes |b| < 5° and longitudes ℓ = 30°–215° in the r, i, and Hα filters using the Wide Field Camera (WFC) on the 2.5-m Isaac Newton Telescope (INT) in La Palma. We present the first quality-controlled and globally calibrated source catalogue derived from the survey, providing single-epoch photometry for 219 million unique sources across 92 per cent of the footprint. The observations were carried out between 2003 and 2012 at a median seeing of 1.1 arcsec (sampled at 0.33 arcsec pixel−1) and to a mean 5σ depth of 21.2 (r), 20.0 (i), and 20.3 (Hα) in the Vega magnitude system. We explain the data reduction and quality control procedures, describe and test the global re-calibration, and detail the construction of the new catalogue. We show that the new calibration is accurate to 0.03 mag (root mean square) and recommend a series of quality criteria to select accurate data from the catalogue. Finally, we demonstrate the ability of the catalogue's unique (r − Hα, r − i) diagram to (i) characterize stellar populations and extinction regimes towards different Galactic sightlines and (ii) select and quantify Hα emission-line objects. IPHAS is the first survey to offer comprehensive CCD photometry of point sources across the Galactic plane at visible wavelengths, providing the much-needed counterpart to recent infrared surveys

The gamma-glutamyl transpeptidase to platelet ratio (GPR) predicts significant liver fibrosis and cirrhosis in patients with chronic HBV infection in West Africa

BACKGROUND: Simple and inexpensive non-invasive fibrosis tests are highly needed but have been poorly studied in sub-Saharan Africa. METHODS: Using liver histology as a gold standard, we developed a novel index using routine laboratory tests to predict significant fibrosis in patients with chronic HBV infection in The Gambia, West Africa. We prospectively assessed the diagnostic accuracy of the novel index, Fibroscan, aspartate transaminase-to-platelet ratio index (APRI), and Fib-4 in Gambian patients with CHB (training set) and also in French and Senegalese CHB cohorts (validation sets). RESULTS: Of 135 consecutive treatment-naïve patients with CHB who had liver biopsy, 39% had significant fibrosis (Metavir fibrosis stage ≥F2) and 15% had cirrhosis (F4). In multivariable analysis, gamma-glutamyl transpeptidase (GGT) and platelet count were independent predictors of significant fibrosis. Consequently, GGT-to-platelet ratio (GPR) was developed. In The Gambia, the area under the receiver operating characteristic curve (AUROC) of the GPR was significantly higher than that of APRI and Fib-4 to predict ≥F2, ≥F3 and F4. In Senegal, the AUROC of GPR was significantly better than Fib-4 and APRI for ≥F2 (0.73, 95% CI 0.59 to 0.86) and better than Fib-4 and Fibroscan for ≥F3 (0.93, 0.87 to 0.99). In France, the AUROC of GPR to diagnose ≥F2 (0.72, 95% CI 0.59 to 0.85) and F4 (0.87, 0.76 to 0.98) was equivalent to that of APRI and Fib-4. CONCLUSIONS: The GPR is a more accurate routine laboratory marker than APRI and Fib-4 to stage liver fibrosis in patients with CHB in West Africa. The GPR represents a simple and inexpensive alternative to liver biopsy and Fibroscan in sub-Saharan Africa