2,059 research outputs found
Study of W± boson in the ALICE muon spectrometer: considerations and analysis using the HLT tool
W± bosons produced in proton-proton collisions can be observed in the ALICE muon spectrometer via their decay into single muons at a transverse momentum, pt ~ Mw/2 40 GeV/c. However the identification of these single muons is complicated by a large amount of muonic background, especially in the low pt region. Therefore, it is necessary to apply precise pt cuts below the region of interest. This can be done by means of the High Level Trigger (HLT). In this paper we present the performance of detecting high pt muons at the HLT level. In order to improve the momentum resolution of the L0 trigger, fast clusterization of the tracking chambers together with L0 trigger matching and fast tracking reconstruction is applied. This will reduce the background in the high pt muon analysis
Elemental, phytochemical, and toxicological assessment of Cissus rotundifolia (Forssk.) Vahl
Cissus rotundifolia (Forssk.) Vahl. (Vitaceae) is a wild plant that is commonly used by communities from rural areas as a food and medicine. There are limited studies on the phytochemical composition and the impact of soil quality on the elemental distribution in this plant. In this study, we report a phytochemical analysis to identify the phytocompounds responsible for the reported biological activities of C. rotundifolia. We also examined the impact of soil quality on elemental uptake by the edible parts of C. rotundifolia collected from eight geographical locations in KwaZulu-Natal (South Africa) to assess the nutritional benefits and potential heavy metal toxicities. Three secondary metabolites (stigmasterol, β-sitosterol, and pheophytin a) were isolated, and their structures were characterised by high-resolution mass spectrometry and nuclear magnetic resonance data. The plant was found to contribute adequately to the recommended dietary allowances for essential nutrients without exceeding tolerable upper intake limits and with low concentrations of toxic heavy metals. The average concentrations of microelements in the edible parts were found to be in decreasing order of Fe>Mn>Se>Zn>Cu>Cr>Ni>Co. The bioaccumulation factors indicate that the plant controls the uptake of metals from the soil and would make a good indicator and biological monitor for cadmium toxicity. However, a health risk assessment exposed carcinogenic risks on regular consumption of the plant obtained from sites close to pollution sources, such as roads and landfills. The findings from this study show the synergies when consuming medicinal plants and provide evidence for C. rotundifolia as a nutraceutical.
Significance:
This study provides additional scientific knowledge on the phytochemical composition of C. rotundifolia. Three phytocompounds (stigmasterol, β-sitosterol, and pheophytin a) were isolated, and their presence may be correlated to this plant’s antidiabetic, anti-inflammatory, and antibacterial properties. This study shows that C. rotundifolia contributes adequately to the recommended dietary allowances for essential elements, and the plant is safe for human consumption if collected from non-polluted sites. The carcinogenic and non-carcinogenic estimates for the toxic metals due to consumption of the plant signify the possibility of developing cancer over time if the plant is consumed frequently from polluted sites
Elemental, phytochemical, and toxicological assessment of Cissus rotundifolia (Forssk.) Vahl
Cissus rotundifolia (Forssk.) Vahl. (Vitaceae) is a wild plant that is commonly used by communities from rural
areas as a food and medicine. There are limited studies on the phytochemical composition and the impact
of soil quality on the elemental distribution in this plant. In this study, we report a phytochemical analysis
to identify the phytocompounds responsible for the reported biological activities of C. rotundifolia. We also
examined the impact of soil quality on elemental uptake by the edible parts of C. rotundifolia collected from
eight geographical locations in KwaZulu-Natal (South Africa) to assess the nutritional benefits and potential
heavy metal toxicities. Three secondary metabolites (stigmasterol, β-sitosterol, and pheophytin a) were
isolated, and their structures were characterised by high-resolution mass spectrometry and nuclear magnetic
resonance data. The plant was found to contribute adequately to the recommended dietary allowances for
essential nutrients without exceeding tolerable upper intake limits and with low concentrations of toxic heavy
metals. The average concentrations of microelements in the edible parts were found to be in decreasing
order of Fe>Mn>Se>Zn>Cu>Cr>Ni>Co. The bioaccumulation factors indicate that the plant controls the
uptake of metals from the soil and would make a good indicator and biological monitor for cadmium toxicity.
However, a health risk assessment exposed carcinogenic risks on regular consumption of the plant obtained
from sites close to pollution sources, such as roads and landfills. The findings from this study show the
synergies when consuming medicinal plants and provide evidence for C. rotundifolia as a nutraceutical.
SIGNIFICANCE : This study provides additional scientific knowledge on the phytochemical composition of C. rotundifolia.
Three phytocompounds (stigmasterol, β-sitosterol, and pheophytin a) were isolated, and their presence may
be correlated to this plant’s antidiabetic, anti-inflammatory, and antibacterial properties. This study shows
that C. rotundifolia contributes adequately to the recommended dietary allowances for essential elements,
and the plant is safe for human consumption if collected from non-polluted sites. The carcinogenic and
non-carcinogenic estimates for the toxic metals due to consumption of the plant signify the possibility of
developing cancer over time if the plant is consumed frequently from polluted sites.The University of KwaZulu-Natal and the South
African National Research Foundation.http://www.sajs.co.zahj2023Chemistr
No evidence of an 11.16 MeV 2+ state in 12C
An experiment using the 11B(3He,d)12C reaction was performed at iThemba LABS
at an incident energy of 44 MeV and analyzed with a high energy-resolution
magnetic spectrometer, to re-investigate states in 12C published in 1971. The
original investigation reported the existence of an 11.16 MeV state in 12C that
displays a 2+ nature. In the present experiment data were acquired at
laboratory angles of 25-, 30- and 35- degrees, to be as close to the c.m.
angles of the original measurements where the clearest signature of such a
state was observed. These new low background measurements revealed no evidence
of the previously reported state at 11.16 MeV in 12C
Studies of the Giant Dipole Resonance in Al, Ca, Fe, Ni and Pb with high energy-resolution inelastic proton scattering under 0
A survey of the fine structure of the Isovector Giant Dipole Resonance
(IVGDR) was performed, using the recently commissioned zero-degree facility of
the K600 magnetic spectrometer at iThemba LABS. Inelastic proton scattering at
an incident energy of 200 MeV was measured on Al, Ca, Fe,
Ni and Pb. A high energy resolution (
40 keV FWHM) could be achieved after utilising faint-beam and
dispersion-matching techniques. Considerable fine structure is observed in the
energy region of the IVGDR and characteristic energy scales are extracted from
the experimental data by means of a wavelet analysis. The comparison with
Quasiparticle-Phonon Model (QPM) calculations provides insight into the
relevance of different giant resonance decay mechanisms. Photoabsorption cross
sections derived from the data assuming dominance of relativistic Coulomb
excitation are in fair agreement with previous work using real photons.Comment: 15 pages, 15 figure
COVID deaths in South Africa: 99 days since South Africa’s first death
Background. Understanding the pattern of deaths from COVID-19 in South Africa (SA) is critical to identifying individuals at high risk of dying from the disease. The Minister of Health set up a daily reporting mechanism to obtain timeous details of COVID-19 deaths from the provinces to track mortality patterns.Objectives. To provide an epidemiological analysis of the first COVID-19 deaths in SA.Methods. Provincial deaths data from 28 March to 3 July 2020 were cleaned, information on comorbidities was standardised, and data were aggregated into a single data set. Analysis was performed by age, sex, province, date of death and comorbidities.Results. SA reported 3 088 deaths from COVID-19, i.e. an age-standardised death rate of 64.5 (95% confidence interval (CI) 62.3 - 66.8) deaths per million population. Most deaths occurred in Western Cape (65.5%) followed by Eastern Cape (16.8%) and Gauteng (11.3%). The median age of death was 61 years (interquartile range 52 - 71). Males had a 1.5 times higher death rate compared with females. Individuals with two or more comorbidities accounted for 58.6% (95% CI 56.6 - 60.5) of deaths. Hypertension and diabetes were the most common comorbidities reported, and HIV and tuberculosis were more common in individuals aged <50 years.Conclusions. Data collection for COVID-19 deaths in provinces must be standardised. Even though the data had limitations, these findings can be used by the SA government to manage the pandemic and identify individuals who are at high risk of dying from COVID-19
Wavelet signatures of -splitting of the Isoscalar Giant Quadrupole Resonance in deformed nuclei from high-resolution (p,p) scattering off Nd
The phenomenon of fine structure of the Isoscalar Giant Quadrupole Resonance
(ISGQR) has been studied with high energy-resolution proton inelastic
scattering at iThemba LABS in the chain of stable even-mass Nd isotopes
covering the transition from spherical to deformed ground states. A wavelet
analysis of the background-subtracted spectra in the deformed 146,148,150Nd
isotopes reveals characteristic scales in correspondence with scales obtained
from a Skyrme RPA calculation using the SVmas10 parameterization. A semblance
analysis shows that these scales arise from the energy shift between the main
fragments of the K = 0, 1 and K = 2 components.Comment: 7 pages, 6 figure
Binary projectile fragmentation of 12C at an incident energy of 33.3 MeV/nucleon
Direct binary projectile fragmentation is being investigated for the case where a 400 MeV 12C projectile breaks up into an particle and a 8Be fragment in the interaction with a thin 93Nb and 197Au target. While the 8Be fragments were measured at 9 , the correlated particles were detected in an angular range between 16 and 30 on the opposite side of the beam. From the preliminary results presented here one may obtain information on the amount of quasi-elastic fragmentation (both fragments do not suffer any further interactions after they are produced). These experimental results indicate that the quasi-elastic break-up process is the dominant contribution to the measured correlation spectra. As was also observed in earlier work, the most forward quasi-elastically emitted particles have energies exceeding the beam velocity
Fine structure of the isoscalar giant quadrupole resonance in 40Ca due to Landau damping?
The fragmentation of the Isoscalar Giant Quadrupole Resonance (ISGQR) in 40Ca
has been investigated in high energy-resolution experiments using proton
inelastic scattering at E_p = 200 MeV. Fine structure is observed in the region
of the ISGQR and its characteristic energy scales are extracted from the
experimental data by means of a wavelet analysis. The experimental scales are
well described by Random Phase Approximation (RPA) and second-RPA calculations
with an effective interaction derived from a realistic nucleon-nucleon
interaction by the Unitary Correlation Operator Method (UCOM). In these results
characteristic scales are already present at the mean-field level pointing to
their origination in Landau damping, in contrast to the findings in heavier
nuclei and also to SRPA calculations for 40Ca based on phenomenological
effective interactions, where fine structure is explained by the coupling to
two-particle two-hole (2p-2h) states.Comment: Phys. Lett. B, in pres
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