Detection in the presence of reverberation is often difficult in active sonar, due to the reflection/diffusion/diffraction of the transmitted signal by the ocean surface, ground, and volume. A ...modelization of reverberation is often used to improve detection because classical algorithms are inefficient. A commonly used reverberation model is colored and nonstationary noise. This model leads to elaborate detection algorithms which normalize and whiten reverberation. In this paper, we focus on a more deterministic model which considers reverberation as a sum of echoes issued from the transmitted signal. The Principal Component Inverse (PCI) algorithm is used with this model to estimate and delete the reverberation echoes. A rank analysis of the observation matrix shows that PCI is efficient in this configuration under some conditions, such as when the transmitted signal is Frequency Modulated. Both methods are validated with real sonar surface reverberation noise. We show that whitening has poor performance when reverberation and target echo have the same properties, while PCI maintains the same performance whatever the reverberation characteristics. Further, we extend the algorithms to spatio-temporal data. We propose a new algorithm for PCI which allows better echo separation. This new method is shown to be more efficient on real spatio-temporal data.
Introduction
Recommendations on the optimal frequency of plasma viral load (pVL) monitoring in children living with HIV (CLWH) who are stable on combination antiretroviral therapy (cART) are ...inconsistent. This study aimed to determine the impact of annual versus semi‐annual pVL monitoring on treatment outcomes in Asian CLWH.
Methods
Data on children with perinatally acquired HIV aged <18 years on first‐line, non‐nucleoside reverse transcriptase inhibitor‐based cART with viral suppression (two consecutive pVL <400 copies/mL over a six‐month period) were included from a regional cohort study; those exposed to prior mono‐ or dual antiretroviral treatment were excluded. Frequency of pVL monitoring was determined at the site‐level based on the median rate of pVL measurement: annual 0.75 to 1.5, and semi‐annual >1.5 tests/patient/year. Treatment failure was defined as virologic failure (two consecutive pVL >1000 copies/mL), change of antiretroviral drug class, or death. Baseline was the date of the second consecutive pVL <400 copies/mL. Competing risk regression models were used to identify predictors of treatment failure.
Results
During January 2008 to March 2015, there were 1220 eligible children from 10 sites that performed at least annual pVL monitoring, 1042 (85%) and 178 (15%) were from sites performing annual (n = 6) and semi‐annual pVL monitoring (n = 4) respectively. Pre‐cART, 675 children (55%) had World Health Organization clinical stage 3 or 4, the median nadir CD4 percentage was 9%, and the median pVL was 5.2 log10 copies/mL. At baseline, the median age was 9.2 years, 64% were on nevirapine‐based regimens, the median cART duration was 1.6 years, and the median CD4 percentage was 26%. Over the follow‐up period, 258 (25%) CLWH with annual and 40 (23%) with semi‐annual pVL monitoring developed treatment failure, corresponding to incidence rates of 5.4 (95% CI: 4.8 to 6.1) and 4.3 (95% CI: 3.1 to 5.8) per 100 patient‐years of follow‐up respectively (p = 0.27). In multivariable analyses, the frequency of pVL monitoring was not associated with treatment failure (adjusted hazard ratio: 1.12; 95% CI: 0.80 to 1.59).
Conclusions
Annual compared to semi‐annual pVL monitoring was not associated with an increased risk of treatment failure in our cohort of virally suppressed children with perinatally acquired HIV on first‐line NNRTI‐based cART.
Pregnant women with an elevated viral load of hepatitis B virus (HBV) have a risk of transmitting infection to their infants, despite the infants' receiving hepatitis B immune globulin.
In this ...multicenter, double-blind clinical trial performed in Thailand, we randomly assigned hepatitis B e antigen (HBeAg)-positive pregnant women with an alanine aminotransferase level of 60 IU or less per liter to receive tenofovir disoproxil fumarate (TDF) or placebo from 28 weeks of gestation to 2 months post partum. Infants received hepatitis B immune globulin at birth and hepatitis B vaccine at birth and at 1, 2, 4, and 6 months. The primary end point was a hepatitis B surface antigen (HBsAg)-positive status in the infant, confirmed by the HBV DNA level at 6 months of age. We calculated that a sample of 328 women would provide the trial with 90% power to detect a difference of at least 9 percentage points in the transmission rate (expected rate, 3% in the TDF group vs. 12% in the placebo group).
From January 2013 to August 2015, we enrolled 331 women; 168 women were randomly assigned to the TDF group and 163 to the placebo group. At enrollment, the median gestational age was 28.3 weeks, and the median HBV DNA level was 8.0 log
IU per milliliter. Among 322 deliveries (97% of the participants), there were 319 singleton births, two twin pairs, and one stillborn infant. The median time from birth to administration of hepatitis B immune globulin was 1.3 hours, and the median time from birth to administration of hepatitis B vaccine was 1.2 hours. In the primary analysis, none of the 147 infants (0%; 95% confidence interval CI, 0 to 2) in the TDF group were infected, as compared with 3 of 147 (2%; 95% CI, 0 to 6) in the placebo group (P=0.12). The rate of adverse events did not differ significantly between groups. The incidence of a maternal alanine aminotransferase level of more than 300 IU per liter after discontinuation of the trial regimen was 6% in the TDF group and 3% in the placebo group (P=0.29).
In a setting in which the rate of mother-to-child HBV transmission was low with the administration of hepatitis B immune globulin and hepatitis B vaccine in infants born to HBeAg-positive mothers, the additional maternal use of TDF did not result in a significantly lower rate of transmission. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development; ClinicalTrials.gov number, NCT01745822 .).
L'organisation des transports périnatals a beaucoup évolué en France depuis la création des premiers SMUR pédiatriques et néonatals à la fin des années 1970. Il existe une forte tendance à la ...régionalisation de ces transferts, et toutes les régions métropolitaines possèdent au moins une équipe de SMUR pédiatrique, dédiée ou liée à une réanimation néonatale. Environ 20 % des naissances prématurées ne se produisent pas dans un centre néonatal de niveau adapté et requièrent un transport postnatal. Les équipes effectuant ces transferts disposent des mêmes moyens modernes de monitorage et de prise en charge qu'en réanimation néonatale. Un axe de travail important est l'implication des parents durant la prise en charge et le transfert de leur enfant. Il nous a paru intéressant de comparer nos pratiques par rapport à ce qui se fait en Grande-Bretagne, en Italie et en Suisse. Un focus a été réalisé à chaque fois sur une région de ces pays. Il est rassurant de constater que nos pratiques convergent et que les échanges intereuropéens persistent à une époque où les replis nationaux s'exacerbent.
Although zidovudine prophylaxis decreases the rate of transmission of the human immunodeficiency virus (HIV) type 1 substantially, a large number of infants still become infected. We hypothesized ...that the administration, in addition to zidovudine, of a single dose of oral nevirapine to mothers during labor and to neonates would further reduce transmission of HIV.
We conducted a randomized, double-blind trial of three treatment regimens in Thai women who were receiving zidovudine therapy during the third trimester of pregnancy. In one group, mothers and infants received a single dose of nevirapine (nevirapine-nevirapine regimen); in another, mothers and infants received nevirapine and placebo, respectively (nevirapine-placebo regimen); and in the last, mothers and infants received placebo (placebo-placebo regimen). The infants also received one week of zidovudine therapy and were formula-fed. The end point of the study was infection with HIV in the infants, established by virologic testing.
Between January 15, 2001, and February 28, 2003, a total of 1844 Thai women were enrolled. At the first interim analysis, the independent data monitoring committee stopped enrollment in the placebo-placebo group. Among women who delivered before the interim analysis, the as-randomized Kaplan-Meier estimates of the transmission rates were 1.1 percent (95 percent confidence interval, 0.3 to 2.2) in the nevirapine-nevirapine group and 6.3 percent (95 percent confidence interval, 3.8 to 8.9) in the placebo-placebo group (P<0.001). The final per-protocol transmission rate in the nevirapine-nevirapine group, 1.9 percent (95 percent confidence interval, 0.9 to 3.0), was not significantly inferior to the rate in the nevirapine-placebo group (2.8 percent; 95 percent confidence interval, 1.5 to 4.1). Nevirapine had an effect within subgroups defined by known risk factors such as viral load and CD4 count. No serious adverse effects were associated with nevirapine therapy.
A single dose of nevirapine to the mother, with or without a dose of nevirapine to the infant, added to oral zidovudine prophylaxis starting at 28 weeks' gestation, is highly effective in reducing mother-to-child transmission of HIV.
Des équipes dédiées réalisent des transports médicalisés pédiatriques et néonatals depuis la fin des années 70 en France. Le Groupe francophone de réanimation et urgences pédiatriques (GFRUP) a ...réalisé un état des lieux en 2017 sur la situation en France métropolitaine. Il en ressort qu’il y a maintenant dans chacune des 12 régions métropolitaines au moins 2 équipes de SMUR pédiatrique. Le mode de fonctionnement et l’activité varient beaucoup d’une équipe à l’autre. Cela va de quelques centaines de transports à près de 2000. Les équipes réalisant le plus de transports sont en général dédiées, alors que les autres sont détachées « à la demande » de la réanimation à laquelle elles appartiennent. L’âge limite des enfants transportés varie aussi, certains SMUR ont une activité exclusivement néonatale et, d’autres transportent les enfants jusqu’à 18 ans. Les SMUR pédiatriques évoluent en « s’appropriant » des techniques réservées jusqu’à présent aux services de réanimation, les exemples en sont la ventilation par oscillation à haute fréquence, l’hypothermie thérapeutique active, l’assistance circulatoire extracorporelle et l’échographie transthoracique. La formation initiale et continue, médicale et paramédicale, fait partie des missions universitaires confiées aux SMUR pédiatriques. La place des parents lors des soins est une problématique qui s‘est imposée en réanimation et il en est de même pour les équipes de transport. En presque un demi-siècle le rôle des SMUR pédiatriques a grandement évolué, de structure de sauvetage en dernier recours ils sont devenus un maillon rationnel de la chaîne de soins pédiatriques au sein des réseaux régionaux.
Dedicated teams perform neonatal and pediatric transports since the late 70s in France. In 2017, Groupe francophone de réanimation et urgences pédiatriques (GFRUP) has ordered a survey about the French organization of pediatric retrieval teams. There are at least two teams in each of the 12 regions of metropolitan France. The amount of transfers varies widely from one team to another (a few hundreds to nearly 2000). Teams performing most transfers are dedicated while the other ones are “on demand”. There is a great variation in the age limit: exclusive neonatal team for some and until 18 years for others. Pediatric retrieval teams are able to use sophisticated techniques which used to be usable only in intensive care unit like ventilation with high frequency oscillation, active therapeutic hypothermia, extracorporeal membrane oxygenation and trans-thoracic echocardiography. Initial and continuing training are part of the duty of many university retrieval teams. Family centered care is now a key point in transfers’ management. In half a century, neonatal and pediatric transport has widely evolved, and is now a recognized part of the healthcare chain inside perinatal and pediatric networks.
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