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This article presents a computational framework for the concise encoding of an ensemble of persistence diagrams, in the form of weighted Wasserstein barycenters Turner et al. (2014), Vidal et al. (2020) of a dictionary of atom diagrams. We introduce a multi-scale gradient descent approach for the efficient resolution of the corresponding minimization problem, which interleaves the optimization of the barycenter weights with the optimization of the atom diagrams. Our approach leverages the analytic expressions for the gradient of both sub-problems to ensure fast iterations and it additionally exploits shared-memory parallelism. Extensive experiments on public ensembles demonstrate the efficiency of our approach, with Wasserstein dictionary computations in the orders of minutes for the largest examples. We show the utility of our contributions in two applications. First, we apply Wassserstein dictionaries to data reduction and reliably compress persistence diagrams by concisely representing them with their weights in the dictionary. Second, we present a dimensionality reduction framework based on a Wasserstein dictionary defined with a small number of atoms (typically three) and encode the dictionary as a low dimensional simplex embedded in a visual space (typically in 2D). In both applications, quantitative experiments assess the relevance of our framework. Finally, we provide a C++ implementation that can be used to reproduce our results.

Integrated Management of Neonatal and Childhood Illness (IMNCI) has been part of the national strategy for child health in Lao Peoples Democratic Republic since 2003. The program, while running for an extended period, has faced multiple challenges including maintaining the teaching quality for the implementation of the IMNCI guidelines and a structure to enable and support healthcare workers trained to apply the training in their workplace. A revised training model that focused on building skills for teaching according to adult learning principles in a pool of facilitators, a practical and hands-on training workshop for healthcare workers, and the establishment of a program of health center supervision was developed and implemented in three provinces. Participants in the revised model reported increased confidence in implementing IMNCI guidelines, they demonstrated competence in the steps of IMNCI and on follow-up assessment at a supervision visit were found to have improved patient care through the measurement of pediatric case management scores. This study highlights the importance of a focus on education to ensure the translation of guidelines into practice and thereby lead to improvements in the quality of pediatric care. The IMNCI training approach is acceptable and valued by healthcare worker participants.

Background: Hypoxaemia is a common and potentially fatal complication of many childhood, newborn and maternal conditions but often not well recognised or managed in settings where resources are limited. Oxygen itself is often inaccessible due to cost or logistics. This paper describes implementation of oxygen systems in Lao district hospitals, clinical outcomes after 24 months and equipment outcomes after 40 months postimplementation., Methods: A prospective field trial was conducted in 20 district hospitals, including 10 intervention hospitals that received oxygen concentrators and 10 control hospitals. Equipment outcomes were evaluated at baseline, 12, 24 and 40 months. Clinical outcomes of children under 5 years of age with pneumonia were evaluated using a before-and-after controlled study design with information retrospectively collected from medical records., Results: Fourteen (37%), 7 (18%) and 12 (34%) of 38 concentrators required repair at 12, 24 and 40 months, respectively. The proportion of children discharged well increased in intervention (90% (641/712) to 95.2% (658/691)) and control hospitals (87.1% (621/713) to 92.1% (588/606)). In intervention hospitals, case fatality rates for childhood pneumonia fell from 2.7% (19/712) preintervention to 0.80% (6/691) postintervention with no change in control hospitals (1.7% (12/713) preintervention and 2.3% (14/606) postintervention)., Conclusion: Medium-term sustainability of oxygen concentrators in hospitals accompanied by reduced case fatality for childhood pneumonia has been demonstrated in Lao PDR. Significant local engineering capacity to address multiple causes of equipment malfunction was critical. The ongoing requirements and fragile structures within the health system remain major risks to long-term sustainability., Competing Interests: Competing interests: None declared.

As data about the causes of neonatal sepsis in low-income countries are inadequate, we reviewed the etiology and antibiotic susceptibilities of bacteremia in young infants in Laos. As Staphylococcus aureus is the leading cause of bacteremia in Lao infants, we also examined risk factors for this infection, in particular the local practice of warming mothers during the first weeks postpartum with hot coals under their beds (hot beds). Clinical and laboratory data regarding infants aged 0-60 days evaluated for sepsis within 72 h of admission to Mahosot Hospital in Vientiane, Laos, were reviewed, and 85 of 1438 (5.9%) infants' blood cultures grew a clinically significant organism. Most common were S. aureus, Escherichia coli and Klebsiella pneumoniae. Whereas no methicillin-resistant S. aureus was found, only 18% of E. coli isolates were susceptible to ampicillin. A history of sleeping on a hot bed with mother was associated with S. aureus bacteremia (odds ratio 4.8; 95% confidence interval 1.2-19.0).

Background: Infantile beriberi is a potentially lethal manifestation of thiamin deficiency, associated with traditional post-partum maternal food avoidance, which persists in the Lao PDR (Laos). There are few data on biochemical markers of infantile thiamin deficiency or indices of cardiac dysfunction as potential surrogate markers., Methodology/principal Findings: A case control study of 47 infants with beriberi and age-matched afebrile and febrile controls was conducted in Vientiane, Laos. Basal and activated erythrocyte transketolase activities (ETK) and activation (α) coefficients were assayed along with plasma brain natriuretic peptide, N-terminal pro-brain natriuretic peptide and troponin T. Basal ETK (and to a lesser extent activated ETK) and plasma troponin T were the only infant biochemical markers that predicted infantile beriberi. A basal ETK ≤ 0.59 micromoles/min/gHb gave a sensitivity (95%CI) of 75.0 (47.6 to 92.7)% and specificity (95%CI) of 85.2 (66.3 to 95.8)% for predicting infantile beriberi (OR (95%CI) 15.9 (2.03-124.2); p = 0.008) (area under ROC curve = 0.80). In contrast, the α coefficient did not discriminate between cases and controls. Maternal basal ETK was linearly correlated with infant basal ETK (Pearson's r = 0.66, p < 0.001). The odds of beriberi in infants with detectable plasma troponin T was 3.4 times higher in comparison to infants without detectable troponin T (OR 3.4, 95%CI 1.22-9.73, p = 0.019). Detectable troponin T had a sensitivity (95%CI) of 78.6 (59.0 to 91.7) % and specificity (95%CI) of 56.1 (39.7 to 71.5) % for predicting infantile beriberi., Conclusions/significance: Basal ETK is a more accurate biochemical marker of infantile beriberi than the activation coefficient. Raised plasma troponin T may be a useful indicator of infantile beriberi in infants at risk and in the absence of other evident causes.

Background: Beriberi occurs in Vientiane, Lao PDR, among breastfed infants. Clinical disease may be the tip of an iceberg with subclinical thiamin deficiency contributing to other illnesses. Thiamin treatment could improve outcome., Methodology/principal Findings: A cohort of 778 sick infants admitted during one year without clinical evidence of beriberi were studied prospectively and erythrocyte transketolase assays (ETK) performed. Biochemical thiamin deficiency was defined both in terms of the activation coefficient (α>31%) and basal ETK activity <0.59 micromoles/min/gHb. Of the 778 infants, median (range) age was 5 (0-12) months, 79.2% were breastfed, 5.1% had α>31% and 13.4 % basal ETK<0.59 micromoles/min/gHb. Infants≥2 months old had a higher frequency of biochemical markers of thiamin deficiency. Mortality was 5.5% but, among infants ≥2 months old, mortality was higher in those with basal ETK<0.59 micromoles/min/gHb (3/47, 6.4%) than in those with basal ETK≥0.59 micromoles/min/gHb (1/146, 0.7%) (P=0.045, relative risk=9.32 (95%CI 0.99 to 87.5)). Multivariate regression analysis indicated that infant age≥2 months and fewer maternal years of schooling were independently associated with infant basal ETK<0.59 micromoles/min/gHb., Conclusions/significance: Clinically unapparent thiamin deficiency is common among sick infants (≥2 months old) admitted to hospital in Vientiane. This may contribute to mortality and a low clinical threshold for providing thiamin to sick infants may be needed.

There is no published information on the causes of bacteremia in the Lao PDR (Laos). Between 2000 and 2004, 4512 blood culture pairs were taken from patients admitted to Mahosot Hospital, Vientiane, Laos, with suspected community-acquired bacteremia; 483 (10.7%) cultures grew a clinically significant community-acquired organism, most commonly Salmonella enterica serovar typhi (50.9%), Staphylococcus aureus (19.0%), and Escherichia coli (12.4%). S. aureus bacteremia was common among infants (69.2%), while children 1-5 years had a high frequency of typhoid (44%). Multi-drug-resistant S. Typhi was rare (6%). On multiple logistic regression analysis, typhoid was associated with younger age, longer illness, diarrhea, higher admission temperature, and lower peripheral white blood cell count than non-typhoidal bacteremia. Empirical parenteral ampicillin and gentamicin would have some activity against approximately 88% of clinically significant isolates at a cost of US $1.4/day, an important exception being B. pseudomallei. Bacteremic infants in this setting require an anti-staphylococcal antibiotic.