The purpose of this paper is to explore machine learning techniques to forecast the oil price. In the era of big data, we investigate whether new automated tools can improve over traditional ...approaches in terms of forecast accuracy. Oil price point and density forecasts are built from 23 methods, including regression trees (random forest, quantile regression forest, xgboost), regularization procedures (elastic net, lasso, ridge), standard econometric models and forecast combinations, besides the structural factor model of Schwartz and Smith (2000). The database contains 315 macroeconomic and financial variables, used to build high-dimensional models. To evaluate the predictive power of each method, an extensive pseudo out-of-sample forecasting exercise is built, in monthly and quarterly frequencies, with horizons from one month up to five years. Overall, the results indicate a good performance of the machine learning methods in the short-run. Up to six months, lasso-based models, oil future prices, VECM and the Schwartz–Smith model provide the best forecasts. At longer horizons, forecast combinations also become relevant. In several cases, the accuracy gains in respect to the random walk forecast are statistically significant and reach two-digit figures, in percentage terms, using the R2 out-of-sample statistic; an expressive achievement compared to the previous literature.
•This paper studies several machine learning techniques to forecast the oil prices.•Random forest, xgboost, lasso, ridge, elastic net, factor models, among others.•Our monthly and quarterly data cover 315 variables from 1991 to 2020.•Automated tools can improve the oil price forecast accuracy over usual approaches.•Many methods beat the random walk: R2 out of sample can reach 42% one month ahead.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
Antibiotics are frequently prescribed for children in the outpatient setting. Although sometimes necessary, antibiotic use is associated with important downstream effects including the development of ...antimicrobial resistance among human and environmental microorganisms. Current outpatient stewardship efforts focus on guiding appropriate antibiotic prescribing practices among providers, but little is known about parents' understanding of antibiotics and appropriate disposal of leftover antibiotics. To help bridge this gap, we conducted a qualitative study to assess parental understanding of their children's antibiotics, their adherence to antibiotic instructions, and their disposal practices. We conducted a semi-structured interview with parents of 13 children diagnosed with acute respiratory illnesses and prescribed antibiotics in an urban outpatient clinic. We found that parents had limited understanding of how antibiotics work. Although they received instructions about antibiotic use during the healthcare visit, adherence to the prescription and appropriate disposal of antibiotics was suboptimal. Limited baseline understanding of antibiotics, their prior experiences with antibiotics, perceptions about their social networks' antibiotic use, and information provided to them by healthcare providers may influence these behaviors. Our findings can inform educational efforts of outpatient stewardship programs to help optimize parental understanding of how to use and dispose of their children's antibiotics.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The elastic distortions nearby the two emerging points of a straight inclined dislocation located in an elastically anisotropic thin foil are expressed with the aid of the integral formalism D.M. ...Barnett and J. Lothe, Phys. Norv. 7 (1973) p.13, an approach complementary to that of the Eshelby's "sextic" formalism. They are included in the calculation of the intensities of diffracted beams in transmission electron microscopy to produce theoretical images, a well known procedure when elastic free surface relaxation is ignored. Examples of theoretical images point out some contrast differences between images calculated with the assumptions of isotropic and anisotropic crystals. These calculations can be simplified for a dislocation normal to the surface and a line direction parallel to a two-fold axis.
Full text
Available for:
BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Purpose
The MAST® D72C test is a phenotypical test which can detect ESBL and AmpC production in
Enterobacterales
. It can also identify the suspected presence of carbapenemase. The aim of the present ...study was to assess the sensitivity and specificity of this test and to discuss its usefulness in laboratories, especially those that use only an automated AST system.
Method
The performance of the MAST® D72C test was assessed against a collection of 119 non-redundant
Enterobacterales
isolates characterized for their content in β-lactamases, and compared with that of the reference double disk synergy test. β-lactamase content was established from phenotypic and genotypic analyses to collect a broad diversity of resistance mechanisms and bacterial strains, including 30 ESBL-producing strains, 32 strains overproducing chromosomal AmpC, 10 strains producing plasmid-encoded AmpC, 12 carbapenemase-producing strains, 13 strains combining the production of several β-lactamases, and 22 strains that produced other β-lactamases.
Results
The sensitivity and specificity for ESBL-detection were comparable with those of the synergy test, 75
versus
72.5%, and 94.9
versus
93.7%, respectively. The sensitivity and specificity for AmpC-detection were 71.7% and 100%, respectively, and sensitivity reached 78.7% if we excluded carbapenem-resistant isolates. Carbapenemase-detection sensitivity was 90%.
Conclusion
These results show that the MAST® D72C test can be a useful tool for the detection of ESBL- and AmpC-production in clinical laboratories.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Characterizing and understanding the multidecadal variations of the continental hydrological cycle is a challenging issue given the limitation of observed data sets. In this paper, a new approach to ...derive twentieth century hydrological reconstructions over France with an hydrological model is presented. The method combines the results of long‐term atmospheric reanalyses downscaled with a stochastic statistical method and homogenized station observations to derive the meteorological forcing needed for hydrological modeling. Different methodological choices are tested and evaluated. We show that using homogenized observations to constrain the results of statistical downscaling help to improve the reproduction of precipitation, temperature, and river flows variability. In particular, it corrects some unrealistic long‐term trends associated with the atmospheric reanalyses. Observationally constrained reconstructions therefore constitute a valuable data set to study the multidecadal hydrological variations over France. Thanks to these reconstructions, we confirm that the multidecadal variations previously noted in French river flows have mainly a climatic origin. Moreover, we show that multidecadal variations exist in other hydrological variables (evapotranspiration, snow cover, and soil moisture). Depending on the region, the persistence from spring to summer of soil moisture or snow anomalies generated during spring by temperature and precipitation variations may explain river flows variations in summer, when no concomitant climate variations exist.
Key Points
A method that combines long‐term atmospheric reanalyses and homogenized observations to obtain the forcing for hydrological modeling is presented
Observed multidecadal river flows variations over France are generally mainly driven by climate variations
Other hydrological variables such as snow cover, evapotranspiration, and soil moisture also show multidecadal variations
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
To investigate the resistance to carbapenems in Enterobacteriaceae and the underlying resistance mechanisms in North Lebanon between 2008 and 2012.
A total of 2767 Enterobacteriaceae isolates ...recovered from clinical samples collected in Nini Hospital (North Lebanon) were screened for a decrease in susceptibility or resistance to ertapenem (MIC >0.25 mg/L). Enterobacteriaceae were similarly screened from 183 faecal samples obtained from non-hospitalized patients. The bacterial isolates were assigned to clonal lineages by PFGE and multilocus sequence typing. Carbapenemase genes, their genetic environment and virulence genes were characterized by molecular approaches.
The rate of Enterobacteriaceae exhibiting a decrease in susceptibility or resistance to ertapenem increased from 0.4% in 2008-10 to 1.6% in 2012 for the clinical isolates recovered from hospitalized patients. Of these isolates, scattered among seven enterobacterial species, 88% produced OXA-48 carbapenemase. However, Escherichia coli represented 73% of the OXA-48-producing Enterobacteriaceae collected in 2012 at this hospital. During the faecal carriage study performed in non-hospitalized patients, E. coli was the only species producing OXA-48. The bla(OXA-48) gene was mainly found within Tn1999.2-type transposons inserted into E. coli chromosomes or in ∼50, ∼62 or ∼85 kb plasmids. The plasmids and chromosomal inserts were related to pOXA-48a. Molecular typing of the isolates revealed clonal diversity of E. coli and Klebsiella pneumoniae producing OXA-48. OXA-48 was observed in all major E. coli phylogroups, including D and B2, and isolates harbouring virulence genes of extra-intestinal pathogenic E. coli. Although not belonging to highly virulent capsular genotypes, the OXA-48-producing K. pneumoniae harboured genes associated with virulence or host colonization.
Horizontal transfer of related plasmids has facilitated the spread of the bla(OXA-48) gene into several Enterobacteriaceae species, including virulent E. coli. Their clonal diversity and the presence of faecal carriers in the community suggest an endemic spread of OXA-48.
Tissue specimens are valuable materials for microbiological diagnosis. The method of tissue processing can have a significant effect on sensitivity. This study aimed to compare different biopsy ...processing methods in terms of efficacy and standardization. Pork tissue artificially inoculated with Staphylococcus aureus and Escherichia coli, and samples of infected human tissue were processed by different methods before culture, and the results compared. Bacterial recovery from artificially inoculated pork tissue was significantly higher by homogenization with GentleMacs Dissociator than with sonication. No significant difference was observed between the GentleMacs Dissociator and manual treatment with a scalpel and vortexing. The microbial yield from homogenized human tissues was significantly higher after homogenization with GentleMacs Dissociator than with the conventional method. Homogenization with the GentleMacs Dissociator retrieves bacteria from tissue effectively. Tissue homogenization with the Dissociator is easy and fast to perform and allows for a high degree of standardization.
Significance and Impact of the Study: Standardization and harmonization of medical laboratories methodologies is essential. The method for processing human tissue and pus samples using the GentleMACS Dissociator is easy and fast to perform and allows for a high degree of standardization while ensuring that bacteria are well‐detected.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Destructive quantum interference effect is implemented in large area molecular junctions to improve signatures of electron-phonon interaction. Vertical molecular junctions based on a cross-conjugated ...anthraquinone layer were fabricated and low-noise transport measurements were performed by acquiring simultaneously the current-voltage characteristics, its second derivative, and the differential conductance. Signatures of vibrational modes excited by inelastic events are present in the whole measured voltage range and superpose to the conductance suppression induced by destructive quantum interference. As a consequence vibrational modes have improved visibility in the low energy window (<80meV). Inelastic electron transport spectroscopy data are compared to infrared attenuated total reflection spectroscopy on Au/anthraquinone thin films. Common vibrational modes can be clearly identified, but inelastic electron tunneling spectroscopy reveals the existence of vibrational modes in a wider energy range (0–400meV) where infrared spectroscopy is lacking.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
PDF
