Investigation of the Strength Development in Tunisian Phosphogypsum-Stabilized Sensitive Clayey Soils: Assess of Geotechnical Properties and Environmental Impact

According to the previous works, the addition of Tunisian phosphogypsum and cement to the clayey soils is able to improve the geotechnical properties of these soils. This addition reduces the swelling problems by making the soil more resistant to water. The degree of success of such a treatment remains dependent on several parameters such as particle size, plasticity, and the chemical and mineralogical composition of soils and the dosage of hydraulic binders. The experimental approach adopted within the framework of this study was oriented towards the characterization of the behavior of three different soil samples in the presence of phosphogypsum and cement at different proportions. To observe this effect, some geotechnical tests were performed such as the Proctor test and the CBR test. The results have shown the improvement in the maximum dry unit weight and the optimum water content depends on the quality of the soil (% clay fraction). The CBR index was influenced by this addition taking into account the properties of the studied soils especially the mineralogical composition. Therefore, to confirm our results, an application of this technique was realized on a real scale.This work proved the reliability of the addition of phosphogypsum and cement to a clay soil with well-defined characteristics. Knowing that the use of the phosphogypsum did not introduce any contamination at the lower layers, either by the heavy metals or by the radioactive elements. The stabilization of sensitive clayey soils with phosphogypsum and cement depends on the quality of the soil to be stabilized, the criteria of the phosphogypsum to be used and the appropriate dosage.

CARACTÉRISATION MICROPALEONTOLOGIQUE DU "RHÉTIEN" DANS L'AXE NORD-SUD (TUNISIE CENTRALE); COMPARAISON AVEC LE RHÉTIEN DE LA DORSALE ET DE LA PLATE-FORME SAHARIENNE

The  micropaleontologic study of the oolitic dolomites from the Fkirine Formation, outcropping along the North-South Axis, allows to characterize the Upper Triassic (Norian?-Rhaetian) in Central Tunisia based on the discovery of Agathammines (Hoyenella inconstans and Agathammina austroalpina) and Aulotortus. This "Rhaetian" benthic foraminiferal assemblage, well known in the Peritethyan areas and locally associated with Gandinella falsofriedli, partially occurs in the type-locality of the Fkirine Formation ("Dorsale Tunisienne") and within the Zerzour Formation  from the Saharian Shelf (Jeffara)

Ostracods distribution in the subsurface sediments of El-Guettiate Sebkha (Skhira, gulf of Gabes). Interest for Holocene palaeoenvironmental reconstruction

A quantitative and qualitative study of the ostracods from the SG1 and BSC2 cores of El-Guettiate Sebkha of Skhira (southeastern Tunisia) has allowed the identification of different associations and the reconstruction of the Holocene palaeoenvironments. Ostracods, rich in species, provide three associations: (i) a marine association containing Aurila prasina BARBIETO-GONZALEZ, 1971, Cushmanidea elongata (BRADY, 1868), Urocythereis oblonga (BRADY, 1866), U. favosa (ROEMER, 1838) (coastal marine), Basselerites berchoni (BRADY, 1869), Semicytherura incongruens (G.W. MÜLLER, 1894), S. paradoxa (G.W. MÜLLER, 1894), S. sella (SARS, 1866), S. ruggierii (PUCCI, 1955), Carinocythereis carinata (ROEMER, 1838) and Paracytheridea depressa (G.W. MÜLLER, 1894) (open marine); (ii) lagoonal association, of variable salinity, comprising Xestoleberis aurantia (BAIRD, 1838), Leptocythere fabaeformis (G.W. MÜLLER, 1894) and Cytherois fischeri (SARS, 1866); (iii) brackish estuarine association subject to estuarine influence as indicated by Cyprideis torosa (JONES, 1850) and Loxoconcha elliptica BRADY, 1868. The ostracods from El-Guettiate Sebkha allow us to recognize discrete palaeoenvironments that can be grouped in three phases: i) the first (6595 ± 120 - 6055 ± 30 years BP) begins with an open lagoon rich in marine ostracods followed by an estuarine lagoon (towards 6595 years BP) characterized by the richness of brackish ostracods and high energy. In the last lagoonal environment (installed towards 6055 years BP), brackish species are dominant and associated with lagoonal taxa; ii) the second phase (6055 ± 30 years BP - 5150 ± 30 years BP) is an estuarine lagoon, subject to a large marine influence in which brackish marine and lagoonal species are present in the same percentages. In this environment, littoral drift currents were responsible for the genesis of sand spits, the termination of environments and the dominance of brackish-water ostracods; iii) The last phase (5150 ± 50 years BP - recent) represents a restricted lagoon (about 5150 years BP) and finally a brackish lagoon evolved towards the sebkha environment under investigation here. This phase includes an unstable period with washover deposits resulting from an extreme climatic event.L'étude quantitative et qualitative des ostracodes des carottes SG1 et BSC2, prélevées au niveau de la Sebkha El-Guettiate de Skhira (Sud - Est Tunisien), nous a permis de reconnaître les trois associations suivantes : (1) association de milieu marin s.l. composée de Aurila prasina BARBIETO-GON-ZALEZ, 1971, Cushmanidea elongata (BRADY, 1868), Urocythereis oblonga (BRADY, 1866), U. favosa (ROEMER, 1838) (marin côtier), Basselerites berchoni (BRADY, 1869), Semicytherura incongruens (G.W. MÜLLER, 1894), S. paradoxa (G.W. MÜLLER, 1894), S. sella (SARS, 1866), S. ruggierii (PUCCI, 1955), Carinocythereis carinata (ROEMER, 1838) et Paracytheridea depressa (G.W. MÜLLER, 1894) (marin ouvert) ; (2) association de milieu lagunaire, à salinité variable, constituée, de Xestoleberis aurantia (BAIRD, 1838), Leptocythere fabaeformis (G.W. MÜLLER, 1894) et Cytherois fischeri (SARS, 1866), (3) association de milieu saumâtre estuarien où se développent Cyprideis torosa (JONES, 1850) et Loxocon-cha elliptica BRADY, 1868. Ces associations révèlent les caractéristiques des paléo-environnements qui se sont succédés, au cours de l'Holocène supérieur, à l'emplacement de la Sebkha El-Guettiate. Trois phases peuvent être reconnues : i) la première phase à caractère lagunaire estuarien dominant (6595 ± 120 à 6055 ± 30 ans B.P.) comprend un environnement lagunaire ouvert riche en ostracodes marins dominants évoluant brutalement vers un environnement lagunaire estuarien. Ce dernier est caractérisé par un évènement de haute énergie, vers 6595 ± 120 ans B.P., révélé par des apports détritiques riches en galets, synchrones à l'enrichissement des ostracodes saumâtres. Ensuite, une lagune s'instal-le vers 6055 ± 30 ans B.P. permettant le développement des ostracodes principalement saumâtres dominants mais aussi lagunaires. ii) la phase suivante (6055 ± 120 à 5150 ± 50 ans B.P.) se distingue par la réapparition des taxons marins associés aux espèces lagunaires et saumâtres traduisant une lagune estuarienne largement ouverte soumise à l'influence des courants de dérive littorale. Ces cou-rants, en édifiant des cordons littoraux, ont entraîné la fermeture du milieu et la fin de la dominance des ostracodes saumâtres. iii) la dernière phase (5150 ± 50 ans B.P. à l'actuel) comprend un milieu caractérisé par la richesse des taxons lagunaires évoluant vers un milieu laguno-saumâtre recevant le dépôt de washover suite à un événement climatique extrême. La lagune, de plus en plus fermée, évo-luera progressivement vers la sebkha actuelle

HOLOCENE ENVIRONMENT CHANGES IN THE HACHICHINA WETLAND (GULF OF GABES, TUNISIA) EVIDENCED BY FORAMINIFERA AND OSTRACODA, GEOCHEMICAL PROXIES AND SEDIMENTOLOGICAL ANALYSES

Four sediment cores, drilled at Younga and Ouadrane Sebkhas (Hachichina wetland), were selected for micropalaeontological, sedimentological, geochronological and geochemical investigation coupled to hierarchical cluster and correspondence analysis. Our research aimed at reconstructing the past biodiversity, the Holocene palaeoenvironmental evolution and the responsible forcing. Subsurface sediments record four major phases: i) the first one is characterized by poorly to very poorly sorted silts, the dominance of the lagoonal/estuarine ostracod and the lagoonal/marine foraminifera and high values of terrestrial geochemical element ratios, such as K/Al and Fe/Al, which indicate an estuarine lagoon; ii) two major marine transgressions, TR1 and TR2, allowing the settlement of widely opened lagoons towards 7160-8680 and 5070-5520 cal yr BP, are marked by the enhancement of the marine/brackish ostracods and marine foraminifera, the improvement of species number, individuals number and H and E index values and of the marine element ratios such as Cl/Al and Sr/Al; iii) the opening of the lagoon is hampered by the action of drift currents allowing the genesis of sand spit and the settlement of a closed lagoon, towards 2610-3610 cal yr BP, characterized by the enhancement of lagoonal/estuarine ostracods and lagoonal/marine foraminifera and the increase of the individuals number; iv) the dominance of the lagoonal/estuarine ostracods and the lagoonal/marine foraminifera and the decline of the species number and density mark a brackish lagoon, also characterized by very poorly sorted silts transported by uniform suspension, which evolves to the actual sebkha. This evolution, within a global climate alteration context, from an estuarine environment to the present sebkha passing by an opened lagoon, is linked to the complex hydrographic setting of the sebkhas and of the Ouadrane Wadi outlet discharging in the Hachichina wetland

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Le Jurassique du sud-tunisien, temoin de la marge africaine de la Tethys : stratigraphie, sedimentologie et micropaleontologie

CNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Caractérisation micropaléontologique du "Rhétien" dans l'axe nord-sud (Tunisie centrale) : comparaison avec le Rhétien de la dorsale et de la plate-forme saharienne

The micropaleontologic study of the oolitic dolomites From the Fkirine Formation, outcropping along the North-South Axis, allows to characterize the Upper Triassic (Norian?-Rhaetian) in Central Tunisia based on the discovery of Agathammines (Hoyenella inconstans and Agathammina austroalpina) and Aulotortus. This "Rhaetian" benthic foraminiferal assemblage, well known in the Peritethyan areas and locally associated with Gandinella falsofriedli, partially occurs in the type-locality of the Fkirine Formation ("Dorsale Tunisienne") and within the Zerzour Formation from the Saharian Shelf (Jeffara)