Reference Zone Research Articles

Habitat selection response of the freshwater shrimp Atyaephyra desmarestii experimentally exposed to heterogeneous copper contamination scenarios

In contaminated aquatic ecosystems, it is expected that organisms suffer some effects caused by the contaminants. However, for mobile organisms inhabiting heterogeneously contaminated ecosystems, the continuous exposure to contaminants can be avoided by moving to less contaminated habitats. The present study evaluated the habitat selection of the freshwater shrimp Atyaephyra desmarestii experimentally exposed to different copper concentrations to verify whether the heterogeneous contamination distribution and the connectivity between habitats with different copper levels could generate a random population distribution similar to metapopulation. The experiments were performed in the HeMHAS (Heterogeneous Multi-Habitat Assay System), a non-forced multi-compartmented exposure system, in which it is possible to simulate the distribution of contaminants in a linear gradient or as patches of contamination. Copper was used to simulate a linear contamination gradient (26 to 105 μg/L Cu) and two patchy scenarios with three contamination levels [reference zone (R: 26 ± 7 μg/L Cu), mixing zone (M: 61 ± 2 μg/L Cu) and disturbed zone (D: 101 ± 12 μg/L Cu)], with two mixing zones or one central mixing zone in a heterogeneous scenario. In the copper gradient scenario, a clear trend of shrimps (59.6 ± 8.0% of the population) moving to the reference zones and an avoidance of 66.7 ± 11.1% of the most contaminated zone were observed. For the patchy scenarios, a random distribution of organisms (34, 36 and 30% for R, M and D zones, respectively) was observed in the scenario with one mixing zone; on the other hand, a slight preference for the reference zones (44.9 ± 4.8%) was evidenced in the scenario with two mixing zones. As shrimps are able to select less contaminated areas, it is highly important to preserve clean zones in heterogeneously contaminated environments, such as the arrangement in meta-ecosystems, as the less- or uncontaminated zones might represent less stressful areas to protect populations against continuous contamination exposure.

Transgenerational endocrine disruption: Does elemental pollution affect egg or nestling thyroid hormone levels in a wild songbird?

Endocrine disrupting chemicals (EDCs) include a wide array of pollutants, such as some metals and other toxic elements, which may cause changes in hormonal homeostasis. In addition to affecting physiology of individuals directly, EDCs may alter the transfer of maternal hormones to offspring, i.e. causing transgenerational endocrine disruption. However, such effects have been rarely studied, especially in wild populations. We studied the associations between environmental elemental pollution (As, Cd, Cu, Ni, Pb) and maternally-derived egg thyroid hormones (THs) as well as nestling THs in great tits (Parus major) using extensive sampling of four pairs of polluted and reference populations across Europe (Finland, Belgium, Hungary, Portugal). Previous studies in these populations showed that breeding success, nestling growth and adult and nestling physiology were altered in polluted zones compared to reference zones. We sampled non-incubated eggs to measure maternally-derived egg THs, measured nestling plasma THs and used nestling faeces for assessing local elemental exposure. We also studied whether the effect of elemental pollution on endocrine traits is dependent on calcium (Ca) availability (faecal Ca as a proxy) as low Ca increases toxicity of some elements. Birds in the polluted zones were exposed to markedly higher levels of toxic elements than in reference zones at the populations in Finland, Belgium and Hungary. In contrast to our predictions, we did not find any associations between overall elemental pollution, or individual element concentrations and egg TH and nestling plasma TH levels. However, we found some indication that the effect of metals (Cd and Cu) on egg THs is dependent on Ca availability. In summary, our results suggest that elemental pollution at the studied populations is unlikely to cause overall TH disruption and affect breeding via altered egg or nestling TH levels with the current elemental pollution loads. Associations with Ca availability should be further studied.

ANALYSIS OF MEDICO-SOCIAL FACTORS DETERMINING THE OUTLOOK IMAGE OF THE SYSTEM OF RENDERING MEDICAL AID TO VICTIMS OF EMERGENCY SITUATIONS IN THE ARCTIC ZONE OF THE RUSSIAN FEDERATION

The article is devoted to the analysis of medico-social factors that determine the outlook Image of the system of medical care for victims in emergency situations in the Arctic Zone of the Russian Federation. The social and economic development of the Russian Arctic zone is a strategic priority of the Russian Federation’s state policy in the Arctic. The goals of Russia’s state policy in the Arctic are to expand the resource base of the Arctic zone, to support the necessary combat potential of groups of troops of the Armed forces of the Russian Federation in the region, to preserve the natural environment, to ensure an adequate level of fundamental and applied scientific research, etc. Strategic priorities of the state policy of the Russian Federation in the Arctic are determined to increase the efforts of the Arctic States in creating a unified regional system of search and rescue, as well as prevention of man-made disasters and elimination of their consequences, including coordination of rescue forces; improving the quality of life of indigenous people and social conditions of economic activity in the Arctic. The main areas of development of the Russian Arctic include hydrocarbon production, fisheries, improvement of transport infrastructure and tourism. Three directions of socio-economic transformation of the Arctic zone of Russia, in the near future, can affect the formation of the appearance of the system of medical care for victims of emergencies: spatial expansion and increase of the economic potential of the Arctic zone of Russia; orientation to the concept of Trinity « innovative economy of energy efficiency sustainable development»; implementation of the concept of the formation in the Arctic eight reference zones of socio-economic development, of which the Kola, Nenets and Yamalo-Nenets reference zones are defined as pilot.

FSI - MRF Coupling Approach For Faster Turbocharger 3D Simulation

<div class="section abstract"><div class="htmlview paragraph">Fluid-Structure Interaction (FSI) simulation approach can be used to simulate a turbocharger. However, this predictive 3D simulation encounters the challenge of a long computational time. The impeller speed can be above 100,000 rpm, and generally a CFD solver limits the maximum movement of the impeller surface per time step. The maximum movement must be a fraction (~0.3) of the cell length, thus the time step will be very small. A Multiple Reference Frame (MRF) approach can reduce computational time by eliminating the need to regenerate the mesh at each time-step to accommodate the moving geometry. A static local reference zone encompassing the impeller is created and the impact of the impeller movement is modeled via a momentum source. However, the MRF approach is not a predictive simulation because the impeller speed must be given by the User. A new simulation approach was introduced that coupled the FSI and MRF approach. Like in the FSI approach, the total moment of the impeller was calculated based on the resultant force acting over the impeller surface. This calculation was conducted for each time-step and the resulted moment was returned back to the solver to update the MRF zone moment. With this coupling approach, the computational time is similar to the MRF approach while maintaining similar accuracy to the FSI predictive approach. The coupling approach was applied to simulate a turbocharger of 15 L diesel engine. The work done by the turbine on the compressor was adjusted to match the impeller speed with the test data. The calculated pressure upstream from the turbine showed a good agreement with test data. The new approach was also used to guide the design of the exhaust manifold for better turbocharger performance.</div></div>

Combustion Chamber Analysis Using CFD for Operation Condition

The gas turbine ignition chamber is a standout amongst the most basic segments to be unlined, in light of the fact that it must guarantee a steady operation in an extensive variety of air/fuel proportion and load. Among a few estimations engaged with the plan of a burning chamber, the reference region is the most vital physical parameter, particularly by the considerable effect on different measurements. As a rule, this parameter must be ascertained from an investigation of the impediments forced both compound responses and optimal design, i.e., in light of ignition process prerequisites and most extreme weight drop passable in the burning chamber, individually. In this way, the point of this paper is research the impact of the reference territory in the speed profile, in the temperature conveyance, in the blending procedure and in the fire conduct, as per the reference zone utilized as a part of the burning chamber. These numerical investigations were completed utilizing ANSYS CFX, contrasting them and the base esteem figured by Lefebvre [5], for a thermodynamic cycle of 600 kW gas turbine motor, conduced in Gate Cycle program. At last, it can be inferred that a few changes in the reference region figured by Lefebvre [4] creates better outcomes, particularly by enhancing the consuming procedure and the conduct of the fire.

Environmental considerations for impact and preservation reference zones for deep-sea polymetallic nodule mining

Development of guidance for environmental management of the deep-sea mining industry is important as contractors plan to move from exploration to exploitation activities. Two priorities for environmental management are monitoring and mitigating the impacts and effects of activities. International regulation of deep-sea mining activities stipulates the creation of two types of zones for local monitoring within a claim, impact reference zones (IRZ) and preservation reference zones (PRZ). The approach used for allocating and assessing these zones will affect what impacts can be measured, and hence taken into account and managed. This paper recommends key considerations for establishing these reference zones for polymetallic nodule mining. We recommend that zones should be suitably large (Recommendation 1) and have sufficient separation (R2) to allow for repeat monitoring of representative impacted and control sites. Zones should be objectively defined following best-practice and statistically robust approaches (R3). This will include the designation of multiple PRZ and IRZ (R4) for each claim. PRZs should be representative of the mined area, and thus should contain high -quality resource (R5) but PRZs in other habitats could also be valuable (R6). Sediment plumes will influence design of PRZ and may need additional IRZ to monitor their effects (R7), which may extend beyond the boundaries of a claim (R8). The impacts of other expected changes should be taken into account (R9). Sharing PRZ design, placement, and monitoring could be considered amongst adjacent claims (R10). Monitoring should be independently verified to enhance public trust and stakeholder support (R11).

The accumulation and redistribution of heavy metals in the water-level fluctuation zone of the Nuozhadu Reservoir, Upper Mekong

The accumulation and redistribution of heavy metals in soil in a water-level fluctuation zone (WLFZ) can create ecological risks to reservoirs and reduce river health. Little is known about how heavy metals are accumulated and redistributed in the WLFZ of reservoirs with a high background value of the heavy metal in soil. The site chosen for this case study is the Nuozhadu mega reservoir in the upper Mekong River Basin, which is held back by a dam with a height exceeding 250 m. Five sampling transects were established around the reservoir. Each transect contained three vertical sampling lines representing three land-use types: forest, farmland, and rubber plantations. Soil samples were collected both in the WLFZ and in the infralittoral reference zone (IRZ), and the concentrations of the heavy metals Zn, Cr, Ni, Cu, Mn, and Fe (%) were measured in these samples. We found that the average concentrations of each of these heavy metals were higher in the WLFZ than in the IRZ. The land-use types, especially the rubber plantations and farmlands, determine the redistribution of the heavy metals in the soil of the WLFZ. The heavy metals Cu, Mn, and Ni increased with increasing elevation within the WLFZ, but the metals Cr and Zn decreased with elevation. The results of analysis of variance indicate that the soil properties had certain differences under different land-use types and inundation durations at various elevations, which partly determined the accumulation and redistribution of heavy metals in the WLFZ. We suggest that long-term monitoring of the concentration of heavy metals is needed for soil and water management in the WLFZ of the Nuozhadu reservoir.

A tree-bordered field as a surrogate for agroforestry in temperate regions: Where does the water go?

There is a renewed interest in temperate agroforestry systems because of their potential to increase biodiversity, sequester carbon and diversify the landscape while maintaining productivity. Little quantitative information is available about the interaction between trees and the crop for water, especially in temperate climate and for tree ages towards the end of an agroforestry cycle. With this study, we quantified the effect of mature poplar trees on soil moisture dynamics in space and time in an agricultural field sown with maize during one growing season. We confirmed the ability of electrical resistivity tomography to study tree-crop interactions for water under field conditions and we delimited an area of influence of the 40-year old trees on the crop of about 15 m. In order to do this, we installed four 30 m electrode transects perpendicular to the field border. Three transects were located next to a tree-bordered part of the field and one reference transect was located along the same border, but without any tree present. We performed seven electrical resistivity tomography (ERT) measurements during the maize growing season and compared the soil moisture distribution and dynamics with and without tree border as a proxy for a mature agroforestry system. We showed that the ERT tomograms in a tree-bordered zone are significantly different from a reference zone without trees along the 30 m of the transect using a single and segmented linear regression analysis. This article shows the potential of ERT to quantify tree-crop-soil interactions for water in agroforestry systems.

Кластерная стратегия развития экономики Кольской опорной зоны в пилотном регионе

Кластерная стратегия развития экономики Кольской опорной зоны в пилотном регионе

Visibility of bony structures around hip prostheses in dual-energy CT: With or without metal artefact reduction software.

The development of dual-energy CT and metal artefact reduction software provides a further chance of reducing metal-related artefacts. However, there have been only a few studies regarding whether MARs practically affect visibility of structures around a metallic hip prosthesis on post-operative CT evaluation. Twenty-seven patients with 42 metallic hip prostheses underwent DECT. The datasets were reconstructed with 70, 90 and 110keV with and without MARs. The areas were classified into 10 zones according to the reference zone. All the images were reviewed in terms of the severity of the beam-hardening artefacts, differentiation of the bony cortex and trabeculae and visualization of trabecular patterns with a three-point scale. The metallic screw diameter was measured in the acetabulum with 110keV images. The scores were the worst on 70keV images without MARs [mean scores:1.84-4.22 (p<0.001-1.000)]. The structures in zone II were best visualized on 110keV (p<0.001-0.011, mean scores: 2.86-5.22). In other zones, there is general similarity in mean scores whether applying MARs or not (p<0.001-0.920). The mean diameter of the screw was 5.85mm without MARs and 3.44mm with MARs (mean reference diameter: 6.48mm). The 110keV images without MARs are best for evaluating acetabular zone II. The visibility of the bony structures around the hip prosthesis is similar in the other zones with or without MARs regardless of keV. MARS may not be needed for the evaluation of the metallic hip prosthesis itself at sufficient high-energy levels; however, MARS still has a role in the evaluation of other soft tissues around the prosthesis.

Development of an anti-EPO antibody detection kit based on lab-on-a-chip and bridging antibody technologies

Immunogenicity is a major concern in the use of biological drugs. In particular, antibody-mediated pure red cell aplasia (PRCA) is a rare condition that is caused by administration of recombinant erythropoietin. There are numerous assay platforms for detect EPO anti-drug antibody (ADA), and most have appropriate assay sensitivity, but in need of improvement in terms of assay turnaround time and user accessibility. Here, the new method was developed based on lab-on-a-chip technology and bridging ELISA. The FREND™ Cartridge is equipped with a microfluidic lateral flow channel, enabling easy, fast and accurate immunoassays with small sample volumes. Biotinylated EPO was immobilized on the avidin-coated solid phase of the test zone in the FREND™ cartridge. Initially, ADA in the serum sample binds to the detector conjugate (EPO-HRP-anti HRP antibody-FL bead) in the conjugation zone, and it flows into the test zone prepared with capture complex (avidin-biotinylated EPO). Unbound detector complexes are captured in the reference zone. The FREND™ system detects and quantifies the fluorescence signals in each zone and then calculates the concentration of EPO ADA in the sample. The FREND™ EPO ADA kit may be useful in local clinics as a rapid method for monitoring patients administered recombinant erythropoietin.

Effects of aircraft noise on annoyance, sleep disorders, and blood pressure among adult residents near the Orio al Serio International Airport (BGY), Italy.

Background:Aircraft noise may cause several non-auditory health effects, including annoyance, sleep disorders, hypertension, cardiovascular diseases, and impaired cognitive skills in children.Objectives:To perform a cross-sectional study among adult residents near the Orio al Serio International Airport (BGY), Italy to investigate the association between aircraft noise, annoyance, sleep disorders, blood pressure levels, and prevalence of hypertension.Methods:Residential addresses of subjects aged 45-70 years were geocoded and classified in three groups according to noise levels: <60 (Reference), 60-65 (Zone A), and 65-75 dBA (Zone B). A sample of subjects was invited to undergo a personal interview and blood pressure measurements. Multiple linear and robust Poisson regression models were used to analyze quantitative and categorical variables, respectively.Results:Between June and September 2013, we enrolled 400 subjects (166 in the Reference Zone, 164 in Zone A, and 70 in Zone B). Compared to the Reference Zone, we found elevated adjusted annoyance scores (day and night) in Zone A (+2.7) and Zone B (+4.0) (p<0.001) and about doubled proportions of severely annoyed subjects (p<0.001). Reported sleep disorders in the previous month were also more frequent in Zones A and B. Sleep disorders in general were 19.9% in the Reference Zone, 29.9% in Zone A, and 35.7% in Zone B (p<0.001).Conclusions:We found a strong association between aircraft noise levels, annoyance, and sleep disorders among adult residents near the Orio al Serio International Airport. We found no relationship with blood pressure levels and prevalence of hypertension.

Optimization of the Bitumen Content of a Basaltic Semi-Granular Bituminous Concrete

Various studies have been conducted in the past by researchers who have proposed diverse solutions to control the premature degradation noted on flexible pavements. It turns out that the binder content remains a parameter so far not mastered and its optimization remains an imperative to produce a quality mix capable of meeting the technical and economic requirements sought in a formulation study. This article mainly aimed to optimize the hydrocarbon binder content of a 0/14 granular class semi-granular bituminous concrete using the Marshall and Duriez method. In the first part of the study, the different constituents were characterized according to the standards in force. The second allowed to describe the methodology used to determine the mixture and calculated the theoretical binder content. A theoretical mixture, entering the reference zone was defined at first. Following the characterization of the mixture in the laboratory, the granulometry curve of the mixture was inserted into the reference zone. This mixture was then preserved for the rest of the study. Then, it was theoretically determined bitumen contents ranging from 5.13% to 5.75% for wealth modules ranging from 3.3% to 3.7%. Thus, the Marshall method was used to characterize the performance of the mixture as a function of the binder content. The results obtained led to the selection of two grades of binders 5.13% and 5.28% for the study of water resistance using the Duriez method. On the basis of the results obtained on the Duriez test, the mixture with a binder content of 5.28% satisfies a good part of the criteria selected. This content corresponds to a wealth module of 3.4%.

Quasi-Static & Dynamic Numerical Modeling of Full Scale NREL 5MW Wind Turbine

Simulations of the National Renewable Energy Laboratory (NREL) 5MW wind turbine under quasi-static Multiple Reference Frame (MRF) and dynamic Sliding Mesh Interface (SMI) methodologies are presented. Two reference zone approach is considered, inertial and moving reference frame. The former contains nacelle and tower, while the later constitutes of the rotor assembly. Predictive capabilities of both simulation techniques are exploited, and verification is performed against the Blade Element Momentum (BEM), and Large Eddy Simulation (LES) results in literature [1], [2]. The simulations are parametrized at variable tip-speed ratios (6, 6.5, 7, 7.5, 8, 8.5,9) and a uniform incoming velocity of 9m/s using unsteady Reynolds-Averaged Navier-Stokes (RANS). The MRF simulation techniques accuracy and robustness are exploited, hereafter key features at various operating conditions inside flow field are identified up to three radii (3R) distance. Aerodynamic torque in the dynamic SMI simulations is observed to oscillate and vary between 2,550 kN m and 2,650 kN m over a revolution. The wake evolution adjacent to the turbine is found to characterized by three massive vortices along with a central vortex which determined the dynamics of the wake. The three blade vortices interact with the central vortex and get dissipated at the 3R distance from the turbine. Immediately behind the tower, increased turbulent intensity levels are reported which gradually reduce after ≈1.5R distance both in the vertical and horizontal direction.

Modeling land suitability for Coffea arabica L. in Central America

Agricultural planning processes at farm to national level are essential for assessing and reacting to land conditions, opportunities, and threats for coffee production. However, lack or uncertainty of information is common during these processes. Bayesian networks can be used to manage these uncertainties. We, therefore, developed the first Bayesian network model for an Agroecological Land Evaluation for Coffea arabica L. (ALECA). A newly developed set of suitability functions was used to populate the nodes in the network. ALECA was then adjusted and validated to Central America. The results show that even without the use of coffee maps as input, ALECA accurately scores the suitability of actual coffee areas for coffee production as higher than that non-coffee areas, and can accurately predict the known order of quality of coffee reference zones in Central America. The results also show that ALECA can be used as a decision-support tool even under data uncertainty.

The Community Structure of Deep-Sea Macrofauna Associated with Polymetallic Nodules in the Eastern Part of the Clarion-Clipperton Fracture Zone

Deep-sea areas characterized by the presence of polymetallic nodules are getting increased attention due to their potential commercial and strategic interest for metals such as nickel, copper and cobalt. The polymetallic nodules occur in areas beyond national jurisdiction, regulated by the International Seabed Authority (ISA). Under exploration contracts, contractors have the obligation to determine the environmental baseline in the exploration areas. Despite a large number of scientific cruises to the central east Pacific Ocean, few published data on the macrofaunal biodiversity and community structure are available for the abyssal fields of the Clarion-Clipperton Fracture Zone (CCFZ). This study focused on the macrofaunal abundance, diversity and community structure in three physically comparable, mineable sites located in the license area of Global Sea Mineral Resources N.V., at ~ 4500 m depth. A homogeneous but diverse macrofaunal community associated with the sediment from polymetallic nodule areas was observed at a scale of 10s to 100s of km. However, slight differences in the abundance and diversity of Polychaeta between sites can be explained by a decline in the estimated flux of particulate organic carbon (POC) along a southeast-northwest gradient, as well as by small differences in sediment characteristics and nodule abundance. The observed homogeneity in the macrofaunal community is an important prerequisite for assigning areas for impact and preservation reference zones. However, a precautionary approach regarding mining activities is recommended, awaiting further research during the exploration phase on environmental factors structuring macrofaunal communities in the CCFZ. For instance, future studies should consider habitat heterogeneity, which was previously shown to structure macrofauna communities at larger spatial scales. Acknowledging the limited sampling in the current study, a large fraction (59-85%; depending on the richness estimator used and the macrofaunal taxon of interest) of the macrofaunal genus/species diversity from the habitat under study was characterized.

Frequencies of erythrocyte nuclear abnormalities and of leucocytes in the fish Barbus peloponnesius correlate with a pollution gradient in the River Bregalnica (Macedonia).

Integrated chemical and biomarker approaches were performed to estimate if there is ongoing toxicity in the River Bregalnica, namely connected with the presence of metals. The study was performed in water, sediment, and barbel (Barbus peloponnesius), collected in two seasons, from two suspected polluted and one reference zones. The water analyses revealed higher mean values in polluted sites for most of the examined physicochemical parameters. Metal concentrations (Zn, Cu, Cd, Mn, Pb, and Fe) in water were more or less constant, whereas in sediment, they were higher at the two polluted locations. Condition factor (CF), as a general health indicator, revealed better overall condition in barbel from the reference site. In general, blood parameters revealed higher values in the polluted localities. Irrespective of sex and/or season, the frequency of micronuclei (MN) and vacuolated nuclei (VN) were with higher rates in polluted sites. Similarly, the frequencies of the leucocytes (Le), binuclei (BN), and irregularly shaped nuclei (ISN) were also significantly increased in the polluted localities, but they seemed prone to be influenced by sex and/or season. However, strong positive correlations between blood biomarkers and most water physicochemical parameters and metal in sediment were estimated. Our data support that the River Bregalnica's lower course receives significant genotoxic pollution, likely via metal industry effluents, agricultural runoff, and domestic sewage, and reinforced the utility of MN and other nuclear abnormalities as sensitive and suitable biomarkers for genotoxicity when used in monitoring studies.

An Enhanced Model Predictive Control for the Artificial Pancreas Using a Confidence Index Based on Residual Analysis of Past Predictions.

Model predictive control (MPC) performance depends on the accuracy of the prediction model implemented by the controller. Complex physiology and modeling limitations often prevent the ability to provide long and accurate glucose predictions, which results in the need to account for prediction errors. Optimal insulin dosage by Zone-MPC is calculated by solving an optimization problem in which a scalar index is minimized by penalizing relative input deviations and glucose predictions out of the reference zone. The controller's tuning parameters are the penalties on the input variable (insulin). Positive and negative relative inputs are penalized differently. A dynamic adaptation of the tuning parameters based on the accuracy of the model in recent history is implemented in this article and compared in silico to aggressive and conservative tunings of the same controller structure. Similar average glucose and time in the safe glucose range (70-180 mg/dL) are achieved for the adaptive design and traditional controller configurations. However, percentage time under 70 mg/dL is significantly reduced, both for announced meals using bolus compensation and unannounced meals with a meal detection algorithm triggered bolus. No differences in the average insulin delivered were observed between the adaptive design and the conservative or aggressive tuning for the bolus strategy, and the adaptive controller delivered less insulin in the other scenario considered. The adaptive strategy provides safe and effective glucose management as well as significant reduction of hypoglycemia events. No abnormal insulin delivery profiles were observed upon the application of the adaptive strategy.

Cenomanian-Turonian roveacrinid microfacies assemblages (Crinoidea, Roveacrinida) from the Tinrhert area (SE Algeria)

In the eastern part of the saharan platform, the Cenomanian-Turonian marine deposits are lying conformably on the red detrital sediments of the so-called Infra-Cenomanian series. In the Hamada de Tinrhert (SE Algeria), the Cretaceous ledges are displaying over great distances a fine-detailed log of the upper Cenomanian-lower Turonian carbonates overlying the lower-middle Cenomanian red-and-greenish gypsum clays. Two sections, Bordj Omar Driss and Oued Takouazet, were thoroughly analyzed to define more precisely the stratigraphical position of the Cenomanian-Turonian boundary (C/TB) in this area. Microfacies analysis of indurated carbonates documented the constant occurrence of roveacrinidal sections on both sides of the Cenomanian-Turonian boundary. Though none of the identified taxa allows to characterize specifically which side of the C/T boundary, their quantitative fluctuations are consistent with those already documented in neighbouring areas and farther beyond. An especially rich and rather constant level, at the top of the coeval Plenus Zone (belemnite biozonation, Boreal realm), occurs close to the Heterohelix event. This conspicuous level provides a supplementary proximity proxy for the Cenomanian-Turonian boundary that should be later on confirmed by the associated ammonites and correlated with the standard reference zones.

Can quantitative contrast-enhanced ultrasonography predict cervical tumor response to neoadjuvant chemotherapy?

ObjectiveTo evaluate the feasibility of quantitative contrast-enhanced ultrasonography (CEUS) for predicting and assessing cervical tumor response to neoadjuvant chemotherapy (NACT). MethodsThirty-eight cases with stage IB2 or IIA cervical cancer were studied using CEUS before and after one cycle of NACT. The quantitative CEUS parameters maximum intensity (IMAX), rise time (RT), time to peak (TTP), and mean transit time (MTT) were compared between cervical tumors and myometrium (reference zone) using Sonoliver software. Absolute and relative changes in quantitative CEUS parameters were also compared among complete response, partial response, and non-responsive groups. Correlations between pre-treatment IMAX and changes in quantitative parameters were assessed after one cycle of NACT. ResultsThere were significant changes in cervical tumor IMAX (P<0.001), RT (P<0.05), and TTP (P<0.05) after one cycle of NACT. According to the Response Evaluation Criteria In Solid Tumors guidelines, the enrollments were divided into complete response, partial response, stable disease and progressive disease groups. There were no significant differences in quantitative CEUS parameters among complete response, partial response, and non-responsive groups (P>0.05). In the stable disease group (n=17), cervical tumor IMAX, RT, and TTP decreased significantly after NACT (P<0.001). The absolute and percentage changes in IMAX were positively correlated with pre-treatment IMAX in all 38 patients (r=0.576, P<0.001 and r=0.429, P<0.001). ConclusionQuantitative CEUS analysis can reveal changes in tumor perfusion following NACT. Tumor perfusion values changes likely precede size changes during the NACT course, and pre-treatment IMAX may be a valuable predictor of cervical tumor perfusion response to NACT with a great decrease in IMAX correlated with better perfusion response.