327 research outputs found

    PRIN Project 2010-11 “Active and recent geodynamics of Calabrian Arc and accretionary complex in the Ionian Sea”: new constraints from geological, geodetic and seismological data

    Get PDF
    This contribution illustrates the preliminary results of our Research Unit in the PRIN Project 2010-11, which focuses on active and recent geodynamics of Calabrian Arc. The integration of the new geological, geodetic and seismological data supports the inferred recent plate boundary reorganization in the central-southern Mediterranean, where the regional GNNS velocity fields point to a deceleration or cessation of Calabrian Arc migration, and to extension along the axis of the Calabrian Arc, accommodated by normal faulting (e.g. Capo Vaticano and Messina Straits (Aloisi et al., 2012; Pepe et al., 2014; Spampinato et al., 2014). The study of the lateral borders of the Arc revealed that oblique strike-slip displacement has occurred during its southeastwards migration. Active dextral transtension is occurring along the NNW-striking Aeolian-Tindari Letojanni fault system, forming the southern boundary of the Arc. It joins to the north other two boundaries characterized by different tectonic regimes, a contractional belt in the southern Tyrrhenian sea, where a tectonic inversion has occurred since the middle Pleistocene, and the extensional one in northeastern Sicily and western Calabria (Palano et al., 2012; Barreca et al., 2014a). Along the northern boundary of the Arc, the so-called Pollino line (onshore) and Sibari Line (offshore), active deformation has been documented on folds growing above blind oblique thrust ramps extending offshore, controlling the present morphobathymetric pattern (Santoro et al., 2013). Although external to the Calabrian Arc, we also devoted attention to the front of the Maghrebian thrust belt in western Sicily where we presented the first evidence of historical co-seismic deformation on a thrust array running from the Belice area to the Sicily Channel (Barreca et al., 2014b). Morphotectonic analysis and fault numeric modeling of uplifted Pleistocene marine terraces and Holocene paleo-shorelines has documented that most of the uplift along the Calabrian Arc is related to regional processes and the residual to coseismic displacement on major faults, both transpressional and transtensional, at the borders, and extensional along the chain axis

    Les rhizobiums d'acacia : biodiversité et taxonomie

    Get PDF
    La diversité des rhizobiums capables de noduler le genre Acacia est étudiée au niveau de deux laboratoires : le laboratoire ORSTOM/ISRA de Dakar s'intéresse plus particulièrement à la diversité des rhizobiums des acacias de zones sèches et le laboratoire ORSTOM/CIRAD de Nogent à celle des acacias de zone humid

    Rhizobial characterization in revegetated areas after bauxite mining.

    Get PDF
    Little is known regarding how the increased diversity of nitrogen-fixing bacteria contributesto the productivity and diversity of plants in complex communities. However, some authorshave shown that the presence of a diverse group of nodulating bacteria is required for dif-ferent plant species to coexist. A better understanding of the plant symbiotic organismdiversity role in natural ecosystems can be extremely useful to define recovery strategies ofenvironments that were degraded by human activities. This study used ARDRA, BOX-PCRfingerprinting and sequencing of the 16S rDNA gene to assess the diversity of root nodulenitrogen-fixing bacteria in former bauxite mining areas that were replanted in 1981, 1985,1993, 1998, 2004 and 2006 and in a native forest. Among the 12 isolates for which the 16SrDNA gene was partially sequenced, eight, three and one isolate(s) presented similarity withsequences of the genera Bradyrhizobium, Rhizobium and Mesorhizobium, respectively. The rich-ness, Shannon and evenness indices were the highest in the area that was replanted theearliest (1981) and the lowest in the area that was replanted most recently (2006)

    High Elective Surgery Cancellation Rate in Malawi Primarily Due to Infrastructural Limitations

    Get PDF
    Background: The provision of safe and timely surgical care is essential to global health care. Low- and middle-income countries have a disproportionate share of the global surgical disease burden and struggle to provide care with the given resources. Surgery cancellation worldwide occurs for many reasons, which are likely to differ between high-income and low-income settings. We sought to evaluate the proportion of elective surgery that is cancelled and the associated reasons for cancellation at a tertiary hospital in Malawi. Methods: This was a retrospective review of a database maintained by the Department of Anesthesiology at Kamuzu Central Hospital in Lilongwe, Malawi. Data were available from August 2011 to January 2015 and included weekday records for the number of scheduled surgeries, the number of cancelled surgeries, and the reasons for cancellation. Descriptive statistics were performed. Results: Of 10,730 scheduled surgeries, 4740 (44.2%) were cancelled. The most common reason for cancellation was infrastructural limitations (84.8%), including equipment shortages (50.9%) and time constraints (33.3%). Provider limitations accounted for 16.5% of cancellations, most often due to shortages of anaesthesia providers. Preoperative medical conditions contributed to 26.3% of cancellations. Conclusion: This study demonstrates a high case cancellation rate at a tertiary hospital in Malawi, attributable primarily to infrastructural limitations. These data provide evidence that investments in medical infrastructure and prevention of workforce brain drain are critical to surgical services in this region

    Arbuscular mycorrhizal fungi diversity in revegetated areas after bauxite mining.

    Get PDF
    Arbuscular mycorrhizal fungi (AMF) are obligatory biotrophs that have a symbiotic evolutionary relationship with about 80% of all terrestrial plant species. The fungus mainly supplies water and nutrients to the plant and receives photoassimilates. The AMF diversity affects both the competition among species and floristic composition of an area. Fluctuations in the population of this group of microorganisms can cause fluctuations in plant populations above ground. In this work, the AMF community profile in areas with different ages of revegetation was evaluated by morphological identification of spores and denaturing gradient gel electrophoresis (DGGE) techniques. We found 12 AMF species and dominance of the species Glomus macrocarpum determined by spore density. Since the richness level observed in each plot was low and there was predominance of one species of AMF, it can be concluded that these areas still present a high degree of disturbance. It was possible to detect complex band profiles by DGGE analyses for the two plant species studied, Visnia latifolia and Cecropia hololeuca. No relationship between AMF diversity and revegetation time was observed in these areas

    Obstetric admissions and outcomes in an intensive care unit in Malawi

    Get PDF
    Background: Despite international commitment to Millennium Development Goal 5, maternal mortality remains high in low- and middle-income countries (LMICs) of sub-Saharan Africa. This is in part due to infrastructure gaps, including availability of intensive care units (ICUs). We sought to use obstetric ICU utilization as a marker of severe maternal morbidity and provide an initial characterization of its relationship with in-hospital mortality. Methods: A prospective observational cohort study of all obstetric subjects admitted to the ICU of Kamuzu Central Hospital in Malawi from September 2016 to March 2018. We reviewed charts at the time of ICU admission to assess the indication for admission, clinical characteristics and laboratory values. Subjects were followed until death or discharge. The primary outcome was in-hospital mortality. Results: One-hundred-and-five obstetric patients were admitted to the study ICU (23% of all admissions). The median age was 26 years. The majority (79%) had undergone recent surgery; 40 (52%) an abdominal postnatal or cesarean hysterectomy and 31 (40%) a cesarean delivery without hysterectomy. Ninety-five percent required mechanical ventilation and 48% required vasopressors. Overall in-hospital mortality was 49%. Conclusions: The proportion of obstetric subjects admitted to the ICU in Malawi is nearly 1 in 4, which exceeds that found in high-income countries by orders of magnitude. Intensive care unit admission was associated with high mortality in this population. Investments in improving infrastructure and care gaps may include addressing available ICU bed and blood-banking needs, and increasing the number of providers trained in managing critical illness among obstetric patients
    corecore