Lojasiewicz exponent of families of ideals, Rees mixed multiplicities and Newton filtrations

We give an expression for the {\L}ojasiewicz exponent of a wide class of n-tuples of ideals $(I_1,..., I_n)$ in \O_n using the information given by a fixed Newton filtration. In order to obtain this expression we consider a reformulation of {\L}ojasiewicz exponents in terms of Rees mixed multiplicities. As a consequence, we obtain a wide class of semi-weighted homogeneous functions $(\mathbb{C}^n,0)\to (\mathbb{C},0)$ for which the {\L}ojasiewicz of its gradient map $\nabla f$ attains the maximum possible value.Comment: 25 pages. Updated with minor change

A CFD analysis of the influence of plenum configurations on gas distribution in a fluidized bed

Fluidized beds are widely used in many industries. The fluidization quality of these units is strongly related to the characteristics of the plenum and distributor (grid). In this work, the effect of different plenum geometries, and gas entrance sizes and locations on the velocity profile above the distributor was analyzed by Computational Fluid Dynamics (CFD). The results showed that flow uniformity above the distributor improved with an increase in the gas inlet diameter and the plenum height. Channeling was observed for the bottom central inlet. Addition-ally, simulations for plenum heights predicted by one of the frequently used correlations (Litz correlation) were also carried out and showed, especially for a bot-tom central gas inlet, a poor quality flow distribution. This behavior indicated that Litz correlation tends to underestimate the plenum height for obtaining a uni-form flow downstream the distributor.Fil: Soria, Jose Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Universidad Nacional del Comahue. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; ArgentinaFil: Ausina, T. M.. Universidad Nacional del Comahue; ArgentinaFil: Mazza, German Delfor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Universidad Nacional del Comahue. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentin

Procalcitonin Predicts Response to Beta-Lactam Treatment in Hospitalized Children with Community-Acquired Pneumonia

BACKGROUND: Antibiotic treatment of community-acquired pneumonia (CAP) in children remains mostly empirical because clinical and paraclinical findings poorly discriminate the principal causes of CAP. Fast response to beta-lactam treatment can be considered a proxy of pneumococcal aetiology. We aimed to identify the best biological predictor of response to beta-lactam therapy in children hospitalized for CAP. METHODS: A retrospective, single-centre cohort study included all consecutive patients 1 month to 16 years old hospitalized in a teaching hospital in Paris, France, because of CAP empirically treated with a beta-lactam alone from 2003 to 2010. Uni- and multivariate analyses were used to study the ability of routine biological parameters available in the Emergency Department to predict a favourable response to beta-lactam (defined as apyrexia within 48 hours of treatment onset). RESULTS: Among the 125 included patients, 85% (106) showed a favourable response to beta-lactam. In multivariate logistic regression, we found procalcitonin (PCT) the only independent predictor of apyrexia (p = 0.008). The adjusted odds ratio for the decadic logarithm of PCT was 4.3 (95% CI 1.5-12.7). At ≥ 3 ng/mL, PCT had 55.7% sensitivity (45.7-65.3), 78.9% specificity (54.4-93.9), 93.7% positive predictive value (84.5-98.2), 24.2% negative predictive value (14.2-36.7), 2.64 positive likelihood ratio (1.09-6.42) and 0.56 negative likelihood ratio (0.41-0.77). In the 4 children with a PCT level ≥ 3 ng/mL and who showed no response to beta-lactam treatment, secondary pleural effusion had developed in 3, and viral co-infection was documented in 1. CONCLUSIONS: PCT is the best independent biologic predictor of favourable response to beta-lactam therapy in children hospitalized for CAP. Thus, a high PCT level is highly suggestive of pneumococcal aetiology. However, a 3-ng/mL cut-off does not seem compatible with daily medical practice, and additional research is needed to further define the role of PCT in managing CAP in children

Incidence of Respiratory Virus-Associated Pneumonia in Urban Poor Young Children of Dhaka, Bangladesh, 2009–2011

Pneumonia is the leading cause of childhood death in Bangladesh. We conducted a longitudinal study to estimate the incidence of virus-associated pneumonia in children aged <2 years in a low-income urban community in Dhaka, Bangladesh.We followed a cohort of children for two years. We collected nasal washes when children presented with respiratory symptoms. Study physicians diagnosed children with cough and age-specific tachypnea and positive lung findings as pneumonia case-patients. We tested respiratory samples for respiratory syncytial virus (RSV), rhinoviruses, human metapneumovirus (HMPV), influenza viruses, human parainfluenza viruses (HPIV 1, 2, 3), and adenoviruses using real-time reverse transcription polymerase chain reaction assays.Between April 2009-March 2011, we followed 515 children for 730 child-years. We identified a total of 378 pneumonia episodes, 77% of the episodes were associated with a respiratory viral pathogen. The overall incidence of pneumonia associated with a respiratory virus infection was 40/100 child-years. The annual incidence of pneumonia/100 child-years associated with a specific respiratory virus in children aged < 2 years was 12.5 for RSV, 6 for rhinoviruses, 6 for HMPV, 4 for influenza viruses, 3 for HPIV and 2 for adenoviruses.Young children in Dhaka are at high risk of childhood pneumonia and the majority of these episodes are associated with viral pathogens. Developing effective low-cost strategies for prevention are a high priority

Is HIV Infection a Risk Factor for Multi-Drug Resistant Tuberculosis? A Systematic Review

BACKGROUND:Tuberculosis (TB) is an important cause of human suffering and death. Human immunodeficiency virus (HIV), multi-drug resistant TB (MDR-TB), and extensive drug resistant tuberculosis (XDR-TB) have emerged as threats to TB control. The association between MDR-TB and HIV infection has not yet been fully investigated. We conducted a systematic review and meta-analysis to summarize the evidence on the association between HIV infection and MDR-TB. METHODS AND RESULTS:Original studies providing Mycobacterium tuberculosis resistance data stratified by HIV status were identified using MEDLINE and ISI Web of Science. Crude MDR-TB prevalence ratios were calculated and analyzed by type of TB (primary or acquired), region and study period. Heterogeneity across studies was assessed, and pooled prevalence ratios were generated if appropriate. No clear association was found between MDR-TB and HIV infection across time and geographic locations. MDR-TB prevalence ratios in the 32 eligible studies, comparing MDR-TB prevalence by HIV status, ranged from 0.21 to 41.45. Assessment by geographical region or study period did not reveal noticeable patterns. The summary prevalence ratios for acquired and primary MDR-TB were 1.17 (95% CI 0.86, 1.6) and 2.72 (95% CI 2.03, 3.66), respectively. Studies eligible for review were few considering the size of the epidemics. Most studies were not adjusted for confounders and the heterogeneity across studies precluded the calculation of a meaningful overall summary measure. CONCLUSIONS:We could not demonstrate an overall association between MDR-TB and HIV or acquired MDR-TB and HIV, but our results suggest that HIV infection is associated with primary MDR-TB. Future well-designed studies and surveillance in all regions of the world are needed to better clarify the relationship between HIV infection and MDR-TB

Commercial Nucleic-Acid Amplification Tests for Diagnosis of Pulmonary Tuberculosis in Respiratory Specimens: Meta-Analysis and Meta-Regression

BACKGROUND: Hundreds of studies have evaluated the diagnostic accuracy of nucleic-acid amplification tests (NAATs) for tuberculosis (TB). Commercial tests have been shown to give more consistent results than in-house assays. Previous meta-analyses have found high specificity but low and highly variable estimates of sensitivity. However, reasons for variability in study results have not been adequately explored. We performed a meta-analysis on the accuracy of commercial NAATs to diagnose pulmonary TB and meta-regression to identify factors that are associated with higher accuracy. METHODOLOGY/PRINCIPAL FINDINGS: We identified 2948 citations from searching the literature. We found 402 articles that met our eligibility criteria. In the final analysis, 125 separate studies from 105 articles that reported NAAT results from respiratory specimens were included. The pooled sensitivity was 0.85 (range 0.36-1.00) and the pooled specificity was 0.97 (range 0.54-1.00). However, both measures were significantly heterogeneous (p<.001). We performed subgroup and meta-regression analyses to identify sources of heterogeneity. Even after stratifying by type of commercial test, we could not account for the variability. In the meta-regression, the threshold effect was significant (p = .01) and the use of other respiratory specimens besides sputum was associated with higher accuracy. CONCLUSIONS/SIGNIFICANCE: The sensitivity and specificity estimates for commercial NAATs in respiratory specimens were highly variable, with sensitivity lower and more inconsistent than specificity. Thus, summary measures of diagnostic accuracy are not clinically meaningful. The use of different cut-off values and the use of specimens other than sputum could explain some of the observed heterogeneity. Based on these observations, commercial NAATs alone cannot be recommended to replace conventional tests for diagnosing pulmonary TB. Improvements in diagnostic accuracy, particularly sensitivity, need to be made in order for this expensive technology to be worthwhile and beneficial in low-resource countries

Evaluation of the SediMax automated microscopy sediment analyzer and the Sysmex UF-1000i flow cytometer as screening tools to rule out negative urinary tract infections

Urinary tract infections (UTI) are highly prevalent in nosocomial and community settings, and their diagnosis is costly and time-consuming. Screening methods represent an important advance towards the final UTI diagnosis, diminishing inappropriate treatment or clinical complications. Automated analyzers have been developed and commercialized to screen and rule out negative urine samples. The aim of this study was to evaluate two of these automated analyzers (SediMax, an automatic sediment analyzer and UF-1000i a flow cytometer) to predict negative urine cultures. A total of 1934 urine samples were analyzed. A very strong correlation for white blood cells (WBC) (rs: 0.928) and a strong correlation for bacteria (BAC) (rs: 0.693) were obtained. We also calculated optimal cut-off points for both autoanalyzers: 18 WBC/μL and 97 BAC/μL for SediMax (sensitivity = 96.25%, specificity = 63.04%, negative predictive value = 97.97%), and 40 WBC/μL and 460 BAC/μL for UF-1000i (sensitivity = 98.13%, specificity = 79.16%, negative predictive value = 99.18%). The use of SediMax and UF- 1000i resulted in a 46.33% and 57.19% reduction of all samples cultured, respectively. In conclusion, both ana- lyzers are good UTI screening tools in our setting

Effect of ionic liquid content on the crystallization kinetics and morphology of Semicrystalline Poly(vinylidene Fluoride)/Ionic liquid blends

The crystallization kinetics of poly(vinylidene fluoride) (PVDF) in blends with the ionic liquid (IL) 1-ethyl-3-methylimidazolium chloride [Emim][Cl] has been studied as a function of [Emim][Cl] content up to 40 wt %. Blends were produced by a solvent casting technique from diluted solutions and solvent evaporation at a temperature higher than the melting point of PVDF followed by cooling to room temperature. Polymer phase, morphology, and crystallization behavior were evaluated. When the molten blend was crystallized from the melt, it was observed that [Emim][Cl] induces nucleation of PVDF in the electroactive and highly polar β-crystalline phase, while pure PVDF crystallizes in the α phase with the same thermal treatments. It is shown that PVDF crystal growth segregates an amorphous phase rich in IL molecules to the surface of the films and that the IL also remains in the spaces between the lamellae or between spherulites as demonstrated by scanning electronic microscopy (SEM) and polarizing optical microscope (POM) images. Differential scanning calorimetry results of isothermal crystallization show the dependence of equilibrium melting temperature and the Avrami exponent with the [Emim][Cl] contentPortuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2020. The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the projects PTDC/BTM-MAT/28237/2017, PTDC/EMD-EMD/28159/2017 and PTDC/FIS-MAC/28157/2017. D.M.C. and C.M.C. also thank to the FCT for grants SFRH/BPD/121526/2016 and SFRH/BPD/112547/2015, respectively. Financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-1-R (AEI/FEDER, UE) (including the FEDER financial support), from the Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID2019-106099RB-C43 / AEI / 10.13039/501100011033. and from the Basque Government Industry and Education Departments under the ELKARTEK, HAZITEK and PIBA (PIBA-2018-06) programs, respectively, are acknowledged. CIBER-BBN is an initiative funded by the VI National R&D&I Plan 2008–2011, Iniciativa Ingenio 2010, Consolider Program. CIBER Actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fun