15 research outputs found
Oil spillage and its impact on the edible mangrove periwinkle, Tympanotonus fuscatus var Radula (l).
Oil spills are a regular occurrence in the oil industry in Nigeria, a process that results in the release of excess hydrocarbons into the environment, negatively impacting plant and animal species. Laboratory and field experiments were conducted on refined oil impacted and fire ravaged mangrove ecosystem to determine the effect of oil spillage on the edible periwinkle Tympanotus fuscatus. The results showed that recolonisation occurred one year after the pollution. Tympanotonus fuscatus was observed in higher numbers than other organisms that attempted recolonisation. Bioassays carried out to investigate the response of T. fuscatus to the refined oil product showed a 96hr Lc50 value of 104.68ml/L.
Keywords: Tympanotonus fuscatus, impact, periwinkle, oil spillage, pollutio
Safety of fish from Nigerian coastal waters
The safety of seafood (fish) from Nigerian coastal waters was studied using heavy metals as index of pollution using finfish samples from four locations (Badagry, Nun River, Sambreiro River, and Cross River). Pb, Cr, and Cd were found to be moderately elevated in 50%, 37.1%, and 35% of the samples respectively. In contrast, Mn, Zn, Cu, and Fe exhibited no discernable elevation. the distribution of heavy metals in finfish and safety status of the fish samples are discussed.
Keywords: Finfish, heavy metals, bioaccumulation, pollution, coastal water, seafood
Seasonal Variations in the Composition and Distribution of Planktonic Fauna in the Eastern Lagos Lagoon, Nigeria
The composition and distribution of planktonic fauna (adult form of
zooplankton and planktonic juvenile forms of higher animals) within the
eastern part of the Lagos Lagoon were investigated in July, 2008 and
March, 2009 representing rainy and dry season respectively. Samples of
water and planktonic fauna were collected from twelve stations within
the eastern axis of the Lagoon and analyzed using standard methods. The
study area had brackish water characteristics with fresh water
condition (0\u2030 salinity across the 12 stations) in the rainy
season whereas the salinity ranged from 11.4\u2030 to 30.5\u2030 in
the dry season. The adult forms zooplankton recorded in the rainy
season were mainly Crustaceans, Chaetognathans and Rotifers while those
collected during dry season belonged to Crustacean, Cnidaria and
Chordata. Crustaceans dominate both adult zooplankton and planktonic
juvenile fauna in the two seasons. The rainy season adult zooplankton
count (515) was lower than that of dry season (580) but the reverse was
the case for the juvenile stages count (520 and 325 in rainy and dry
season respectively). Higher species abundance was recorded for both
adult zooplankton (20) and juvenile stages (10) in rainy than dry
season when 14 and 8 were recorded for the two groups respectively.
Higher values were also of community structure indices (Margalef
species richness and Shannon-Wiener species diversity) were recorded in
the rainy than dry season for the two groups of planktonic fauna. The
findings show the influence of salinity gradients on distribution of
planktonic fauna of the Lagos Lagoon
New Results in the Analysis of the O+Si Elastic Scattering by Modifying the Optical Potential
The elastic scattering of the O+Si system has been analyzed
with a modified potential within the framework of the optical model over a wide
energy range in the laboratory system from 29.0 to 142.5 MeV. This system has
been extensively studied over the years and a number of serious problems has
remained unsolved: The explanation of the anomalous large angle scattering
data; the out-of-phase problem between theoretical predictions and experimental
data; the reproduction of the oscillatory structure near the Coulomb barrier;
the consistent description of angular distributions together with the
excitation functions data are just some of these problems. We propose the use
of a modified potential method to explain these problems over this wide energy
range. This new method consistently improves the agreement with the
experimental data and achieves a major improvement on all the previous Optical
model calculations for this system.Comment: 19 pages with 8 figure
Global Retinoblastoma Presentation and Analysis by National Income Level
Importance: Early diagnosis of retinoblastoma, the most common intraocular cancer, can save both a child's life and vision. However, anecdotal evidence suggests that many children across the world are diagnosed late. To our knowledge, the clinical presentation of retinoblastoma has never been assessed on a global scale. Objectives: To report the retinoblastoma stage at diagnosis in patients across the world during a single year, to investigate associations between clinical variables and national income level, and to investigate risk factors for advanced disease at diagnosis. Design, Setting, and Participants: A total of 278 retinoblastoma treatment centers were recruited from June 2017 through December 2018 to participate in a cross-sectional analysis of treatment-naive patients with retinoblastoma who were diagnosed in 2017. Main Outcomes and Measures: Age at presentation, proportion of familial history of retinoblastoma, and tumor stage and metastasis. Results: The cohort included 4351 new patients from 153 countries; the median age at diagnosis was 30.5 (interquartile range, 18.3-45.9) months, and 1976 patients (45.4) were female. Most patients (n = 3685 84.7%) were from low-and middle-income countries (LMICs). Globally, the most common indication for referral was leukocoria (n = 2638 62.8%), followed by strabismus (n = 429 10.2%) and proptosis (n = 309 7.4%). Patients from high-income countries (HICs) were diagnosed at a median age of 14.1 months, with 656 of 666 (98.5%) patients having intraocular retinoblastoma and 2 (0.3%) having metastasis. Patients from low-income countries were diagnosed at a median age of 30.5 months, with 256 of 521 (49.1%) having extraocular retinoblastoma and 94 of 498 (18.9%) having metastasis. Lower national income level was associated with older presentation age, higher proportion of locally advanced disease and distant metastasis, and smaller proportion of familial history of retinoblastoma. Advanced disease at diagnosis was more common in LMICs even after adjusting for age (odds ratio for low-income countries vs upper-middle-income countries and HICs, 17.92 95% CI, 12.94-24.80, and for lower-middle-income countries vs upper-middle-income countries and HICs, 5.74 95% CI, 4.30-7.68). Conclusions and Relevance: This study is estimated to have included more than half of all new retinoblastoma cases worldwide in 2017. Children from LMICs, where the main global retinoblastoma burden lies, presented at an older age with more advanced disease and demonstrated a smaller proportion of familial history of retinoblastoma, likely because many do not reach a childbearing age. Given that retinoblastoma is curable, these data are concerning and mandate intervention at national and international levels. Further studies are needed to investigate factors, other than age at presentation, that may be associated with advanced disease in LMICs. © 2020 American Medical Association. All rights reserved
Seasonal Variations in the Composition and Distribution of Planktonic Fauna in the Eastern Lagos Lagoon, Nigeria
The composition and distribution of planktonic fauna (adult form of
zooplankton and planktonic juvenile forms of higher animals) within the
eastern part of the Lagos Lagoon were investigated in July, 2008 and
March, 2009 representing rainy and dry season respectively. Samples of
water and planktonic fauna were collected from twelve stations within
the eastern axis of the Lagoon and analyzed using standard methods. The
study area had brackish water characteristics with fresh water
condition (0‰ salinity across the 12 stations) in the rainy
season whereas the salinity ranged from 11.4‰ to 30.5‰ in
the dry season. The adult forms zooplankton recorded in the rainy
season were mainly Crustaceans, Chaetognathans and Rotifers while those
collected during dry season belonged to Crustacean, Cnidaria and
Chordata. Crustaceans dominate both adult zooplankton and planktonic
juvenile fauna in the two seasons. The rainy season adult zooplankton
count (515) was lower than that of dry season (580) but the reverse was
the case for the juvenile stages count (520 and 325 in rainy and dry
season respectively). Higher species abundance was recorded for both
adult zooplankton (20) and juvenile stages (10) in rainy than dry
season when 14 and 8 were recorded for the two groups respectively.
Higher values were also of community structure indices (Margalef
species richness and Shannon-Wiener species diversity) were recorded in
the rainy than dry season for the two groups of planktonic fauna. The
findings show the influence of salinity gradients on distribution of
planktonic fauna of the Lagos Lagoon
Global Retinoblastoma Presentation and Analysis by National Income Level
This cross-sectional analysis reports the retinoblastoma stage at
diagnosis across the world during a single year, investigates
associations between clinical variables and national income level, and
investigates risk factors for advanced disease at diagnosis.
Key PointsQuestionIs the income level of a country of residence
associated with the clinical stage of presentation of patients with
retinoblastoma? FindingsIn this cross-sectional analysis that included
4351 patients with newly diagnosed retinoblastoma, approximately half of
all new retinoblastoma cases worldwide in 2017, 49.1\% of patients from
low-income countries had extraocular tumor at time of diagnosis compared
with 1.5\% of patients from high-income countries. MeaningThe clinical
stage of presentation of retinoblastoma, which has a major influence on
survival, significantly differs among patients from low-income and
high-income countries, which may warrant intervention on national and
international levels.
ImportanceEarly diagnosis of retinoblastoma, the most common intraocular
cancer, can save both a child's life and vision. However, anecdotal
evidence suggests that many children across the world are diagnosed
late. To our knowledge, the clinical presentation of retinoblastoma has
never been assessed on a global scale. ObjectivesTo report the
retinoblastoma stage at diagnosis in patients across the world during a
single year, to investigate associations between clinical variables and
national income level, and to investigate risk factors for advanced
disease at diagnosis. Design, Setting, and ParticipantsA total of 278
retinoblastoma treatment centers were recruited from June 2017 through
December 2018 to participate in a cross-sectional analysis of
treatment-naive patients with retinoblastoma who were diagnosed in 2017.
Main Outcomes and MeasuresAge at presentation, proportion of familial
history of retinoblastoma, and tumor stage and metastasis. ResultsThe
cohort included 4351 new patients from 153 countries; the median age at
diagnosis was 30.5 (interquartile range, 18.3-45.9) months, and 1976
patients (45.4\%) were female. Most patients (n=3685 {[}84.7\%]) were
from low- and middle-income countries (LMICs). Globally, the most common
indication for referral was leukocoria (n=2638 {[}62.8\%]), followed by
strabismus (n=429 {[}10.2\%]) and proptosis (n=309 {[}7.4\%]). Patients
from high-income countries (HICs) were diagnosed at a median age of 14.1
months, with 656 of 666 (98.5\%) patients having intraocular
retinoblastoma and 2 (0.3\%) having metastasis. Patients from low-income
countries were diagnosed at a median age of 30.5 months, with 256 of 521
(49.1\%) having extraocular retinoblastoma and 94 of 498 (18.9\%) having
metastasis. Lower national income level was associated with older
presentation age, higher proportion of locally advanced disease and
distant metastasis, and smaller proportion of familial history of
retinoblastoma. Advanced disease at diagnosis was more common in LMICs
even after adjusting for age (odds ratio for low-income countries vs
upper-middle-income countries and HICs, 17.92 {[}95\% CI, 12.94-24.80],
and for lower-middle-income countries vs upper-middle-income countries
and HICs, 5.74 {[}95\% CI, 4.30-7.68]). Conclusions and RelevanceThis
study is estimated to have included more than half of all new
retinoblastoma cases worldwide in 2017. Children from LMICs, where the
main global retinoblastoma burden lies, presented at an older age with
more advanced disease and demonstrated a smaller proportion of familial
history of retinoblastoma, likely because many do not reach a
childbearing age. Given that retinoblastoma is curable, these data are
concerning and mandate intervention at national and international
levels. Further studies are needed to investigate factors, other than
age at presentation, that may be associated with advanced disease in
LMICs
Search for supersymmetry in final states with missing transverse momentum and three or more b-jets in 139 fb of proton–proton collisions at TeV with the ATLAS detector
International audienceA search for supersymmetry involving the pair production of gluinos decaying via off-shell third-generation squarks into the lightest neutralino is reported. It exploits LHC proton–proton collision data at a centre-of-mass energy TeV with an integrated luminosity of 139 fb collected with the ATLAS detector from 2015 to 2018. The search uses events containing large missing transverse momentum, up to one electron or muon, and several energetic jets, at least three of which must be identified as containing b-hadrons. Both a simple kinematic event selection and an event selection based upon a deep neural-network are used. No significant excess above the predicted background is found. In simplified models involving the pair production of gluinos that decay via off-shell top (bottom) squarks, gluino masses less than 2.44 TeV (2.35 TeV) are excluded at 95% CL for a massless Limits are also set on the gluino mass in models with variable branching ratios for gluino decays to and $t\bar{b}\tilde{\chi }^-_1/\bar{t}b\tilde{\chi }^+_1.
Search for pair production of third-generation leptoquarks decaying into a bottom quark and a -lepton with the ATLAS detector
International audienceA search for pair-produced scalar or vector leptoquarks decaying into a b-quark and a -lepton is presented using the full LHC Run 2 (2015–2018) data sample of 139 fb collected with the ATLAS detector in proton–proton collisions at a centre-of-mass energy of TeV. Events in which at least one -lepton decays hadronically are considered, and multivariate discriminants are used to extract the signals. No significant deviations from the Standard Model expectation are observed and 95% confidence-level upper limits on the production cross-section are derived as a function of leptoquark mass and branching ratio into a -lepton and b-quark. For scalar leptoquarks, masses below 1460 GeV are excluded assuming %, while for vector leptoquarks the corresponding limit is 1650 GeV (1910 GeV) in the minimal-coupling (Yang–Mills) scenario
Luminosity determination in collisions at TeV using the ATLAS detector at the LHC
The luminosity determination for the ATLAS detector at the LHC during Run 2 is presented, with collisions at TeV. The absolute luminosity scale is determined using van der Meer beam separation scans during dedicated running periods in each year, and extrapolated to the physics data-taking regime using complementary measurements from several luminosity-sensitive detectors. The total uncertainties in the integrated luminosities for each individual year of data-taking range from 0.9% to 1.1%, and are partially correlated between years. After standard data-quality selections, the full Run 2 data sample corresponds to an integrated luminosity of fb, i.e. an uncertainty of 0.83%. A dedicated sample of low-pileup data recorded in 2017-18 for precision Standard Model physics measurements is analysed separately, and has an integrated luminosity of pb.The luminosity determination for the ATLAS detector at the LHC during Run 2 is presented, with pp collisions at a centre-of-mass energy TeV. The absolute luminosity scale is determined using van der Meer beam separation scans during dedicated running periods in each year, and extrapolated to the physics data-taking regime using complementary measurements from several luminosity-sensitive detectors. The total uncertainties in the integrated luminosity for each individual year of data-taking range from 0.9% to 1.1%, and are partially correlated between years. After standard data-quality selections, the full Run 2 pp data sample corresponds to an integrated luminosity of , i.e. an uncertainty of 0.83%. A dedicated sample of low-pileup data recorded in 2017–2018 for precision Standard Model physics measurements is analysed separately, and has an integrated luminosity of .The luminosity determination for the ATLAS detector at the LHC during Run 2 is presented, with collisions at TeV. The absolute luminosity scale is determined using van der Meer beam separation scans during dedicated running periods in each year, and extrapolated to the physics data-taking regime using complementary measurements from several luminosity-sensitive detectors. The total uncertainties in the integrated luminosities for each individual year of data-taking range from 0.9% to 1.1%, and are partially correlated between years. After standard data-quality selections, the full Run 2 data sample corresponds to an integrated luminosity of fb, i.e. an uncertainty of 0.83%. A dedicated sample of low-pileup data recorded in 2017-18 for precision Standard Model physics measurements is analysed separately, and has an integrated luminosity of pb