Inactivation of the gene katA or sodA affects the transient entry into the viable but non-culturable response of Staphylococcus aureus in natural seawater at low temperature

We have investigated the fate of Staphylococcus aureus by starving the cells and maintaining them in natural seawater at 22 and 4 °C. At 22 °C, cells developed a long-term survival state where about 0.037% of the initial population remained culturable over more than 7 months, whereas at 4 °C, bacteria lost culturability and transiently entered into the viable but non-culturable state (VBNC). However, after 22 days of entry into the VBNC state, the number of viable cells detected via the direct viable count method decreased significantly. We show here that mutational inactivation of catalase (KatA) or superoxide dismutase (SodA) rendered strains hypersensitive to seawater stress at 4 °C and consequently, part of the seawater lethality on S. aureus at low temperature is mediated by reactive oxygen species (ROS) during microcosm-survival process. Shifting the temperature from 4 to 22 °C of totally non-culturable wild-type cells induced a partial recovery of the population. However, deficiencies in catalase or superoxide dismutase prevent resuscitation ability.     

Mixed nonparametric–parametric probabilistic model for earthquake reliability of an inelastic reinforced concrete frame structure

The paper is devoted to the study of uncertainties when studying buildings under seismic loading. These uncertainties are related to the simplifications used when constructing the model (model uncertainties) and to the numerical data needed at the computation stage (data uncertainties). It has been shown in previous papers that nonparametric models are able, in the case of linear dynamics, to deal simultaneously with these two kinds of uncertainties. The paper presents an extension of this kind of model by taking into account a “mixed” approach for concrete frame structures, which uses a nonparametric model for the part of the structure which behaves linearly and a parametric approach for the parts of the structure (plastic hinges) which behave non-linearly. A numerical application is presented in the case of a residential building.     

Assessment of spatial relationship between groundwater pollution vulnerability and quality indices in Kano,Nigeria

Safeguarding groundwater from pollution is largely a global political decision. These decisions are basically supported by DRASTIC (D=Depth to water, R=Recharge, A=Aquifer media, S=Soil media, T=Topography, I=Impact of vadose zone, C=Hydraulic conductivity) analysis. Furthermore, water quality index (WQI) is an effective tool for groundwater quality evaluation and management. This study identifies the relationship between these two indices [i.e., pollution vulnerability index (PVI) and WQI]. The DRASTIC index of the study area was found to be from 60.4 to 178 characterized by very low, low, medium high, and very high vulnerability constituting of 12.88, 24.38, 34.11, 21.99, and 6.63% of the study area, respectively. In addition, the WQI of the area according to the analyzed parameters is between 10.19 and 55.63. It was established that a good correlation (61%) was found to exist between the two indices; which may be an indication that most pollutants present in the groundwater are likely due to anthropogenic activities on the land surface.     

Subsurface geophysics applied to archaeological investigation of Thabudeos Roman fortress (Biskra,Algeria)

Tahouda, former Roman Thabudeos, is situated 400 km south of Algiers (Algeria). It is one of the fortresses belonging to Roman south defense line in North Africa. This region is archaeologically very poorly known except for surface remains. The geophysical survey formed part of a wider research project designed to record and assess the landscape context of the longest Roman defense line in North Africa. We present the geophysical mapping and imaging using electric resistivity tomography and electromagnetics to help in investigating the subsurface properties of the region. Data were obtained using: (1) Saris resistance meter with up to 25 electrodes spaced at 2 m intervals and lines up to 50 m long. A total of 11 lines was obtained. (2) Geonics EM31, in two dipole configuration modes with 16 lines up to 100 m sampled every meter. These methods prove to be very powerful tools to give insight and locate the anthropologic remains from the surface to a depth of 6 m and outline their geometry. The results obtained by the two methods are consistent above the main remains like walls and rooms.     

Evaluation of the effectiveness of olive cake residue as an expansive soil stabilizer

The quantity of the by-product olive cake residue generated in most parts of the Mediterranean countries continues to increase and expected to double in amount within 10–15 years. This increase intensifies the problems associated with the disposal of this by-product. Olive cake residue has a potential for use as a soil stabilizer and large volumes can be beneficially used. This study is directed toward determining if olive cake residue can be utilized to increase the strength and stability of expansive soils which constitute a costly natural hazard to lightweight structures on shallow foundations. A series of laboratory tests using engineering properties, such as Atterberg limits, moisture-density relationship (compaction), swell, unconfined compressive strength were undertaken to evaluate the effectiveness and performance of the olive cake residue as a soil stabilizer. Test results indicate that an addition of only 3% burned olive waste into the soil causes a reduction in plasticity, volume change and an increase in the unconfined compressive strength. However, it was observed that the presence of burned olive waste in the soil greater than 3% caused an increase in the compressibility and a decrease in the unconfined compressive strength. Test results indicate that the use of olive waste in soil stabilization gives greater benefits to the environment than simply disposing of the by-product, olive cake residue.     

Anomalous heat flow belt along the continental margin of Brazil

International Journal of Earth Sciences - A comprehensive analysis of thermal gradient and heat flow data was carried out for sedimentary basins situated in the continental margin of Brazil (CMB)....     

Biological data from sharks landed within the United Arab Emirates artisanal fishery

Landing site and market surveys of sharks landed along the Arabian Gulf coast of the United Arab Emirates were undertaken between October 2010 and September 2012 to obtain biological data from this artisanal fishery. Data were collected on the size and sex of 12 482 individuals representing 30 species. Maximum sizes of Carcharhinus sorrah, C. amblyrhynchoides and Hemipristis elongata were extended by at least 300?mm total length (TL) compared with published global maxima. The size at 50% maturity was determined for males of five species and this indicated that the males of smaller shark species (<1 000 mm maximum TL) in the fishery were largely mature. For many species, including Loxodon macrorhinus and Mustelus mosis, overall sex ratios were male-biased, indicating that sexual segregation is likely in those species. Furthermore, sex ratios for several species, such as Rhizoprionodon acutus, showed differences across seasons. Overall, the landings contained a high proportion of juveniles, causing concerns about the sustainability of this fishery. Biological parameters of a number of species differed from those recorded earlier for the region, demonstrating a need for additional local data collection to support the development of management measures.