704 research outputs found
The renormalization of the effective Lagrangian with spontaneous symmetry breaking: the SU(2) case
We study the renormalization of the nonlinear effective SU(2) Lagrangian up
to with spontaneous symmetry breaking. The Stueckelberg
transformation, the background field gauge, the Schwinger proper time and heat
kernel method, and the covariant short distance expansion technology, guarantee
the gauge covariance and incooperate the Ward indentities in our calculations.
The renormalization group equations of the effective couplings are derived and
analyzed. We find that the difference between the results gotten from the
direct method and the renormalization group equation method can be quite large
when the Higgs scalar is far below its decoupling limit.Comment: ReVTeX, 12 figures, 22 pages, some bugs are kicked off from programs,
numerical analysis is renew
Practical tips to using formalin-fixed paraffin-embedded tissue archives for molecular diagnostics in a South African setting
BACKGROUND : Formalin-fixed paraffin-embedded (FFPE) tissue archives in hospitals, biobanks,
and others offer a vast collection of extensive, readily available specimens for molecular testing.
Unfortunately, the use of tissue samples for molecular diagnostic applications is challenging;
thus, the forensic pathology FFPE tissue archives in Africa have been a largely unexploited
genetic resource, with the usability of DNA obtainable from these samples being unknown.
INTERVENTION : The study, conducted from January 2015 to August 2016, determined the
usefulness of FFPE tissue as a reliable source of genetic material for successful post-mortem
molecular applications and diagnostics. Formalin-fixed paraffin-embedded tissue samples
were collected and archived from autopsies conducted over 13 years in the forensic medicine
department of the University of Pretoria (Pretoria, South Africa). Deoxyribonucleic acid from
FFPE tissue samples and control blood samples was amplified by high-resolution melt realtime
polymerase chain reaction before sequencing. The procurement parameters and fixation
times were compared with the quantity and quality of the extracted DNA and the efficiency of
its subsequent molecular applications.
LESSONS LEARNT : This study has shown that FFPE samples are still usable in molecular forensics,
despite inadequate sample preparation, and offer immense value to forensic molecular
diagnostics.
RECOMMENDATIONS : FFPE samples fixed in formalin for more than 24 h should still be used in
molecular diagnostics or research, as long as the primer design targets amplicons not exceeding
300 base pairs.The Genomics Research Institute (University of Pretoria) and the South African National Research Foundation.http://www.ajlmonline.orgam2023Chemical PathologyForensic Medicin
Cardiovascular deaths : what do the genes say?
Cardiovascular diseases (CVDs) are ever-increasing, and as such are considered to be one of the most concerning public health burdens worldwide. They remain the leading cause of death across the world (~17.7 million deaths were reported in 2015), accounting for 31% of all global deaths.http://www.samj.org.zaam2023Chemical PathologyForensic Medicin
Light scattering observations of spin reversal excitations in the fractional quantum Hall regime
Resonant inelastic light scattering experiments access the low lying
excitations of electron liquids in the fractional quantum Hall regime in the
range . Modes associated with changes in the charge and
spin degrees of freedom are measured. Spectra of spin reversed excitations at
filling factor and at identify a structure
of lowest spin-split Landau levels of composite fermions that is similar to
that of electrons. Observations of spin wave excitations enable determinations
of energies required to reverse spin. The spin reversal energies obtained from
the spectra illustrate the significant residual interactions of composite
fermions. At energies of spin reversal modes are larger but
relatively close to spin conserving excitations that are linked to activated
transport. Predictions of composite fermion theory are in good quantitative
agreement with experimental results.Comment: Submitted to special issue of Solid State Com
Superselectors: Efficient Constructions and Applications
We introduce a new combinatorial structure: the superselector. We show that
superselectors subsume several important combinatorial structures used in the
past few years to solve problems in group testing, compressed sensing,
multi-channel conflict resolution and data security. We prove close upper and
lower bounds on the size of superselectors and we provide efficient algorithms
for their constructions. Albeit our bounds are very general, when they are
instantiated on the combinatorial structures that are particular cases of
superselectors (e.g., (p,k,n)-selectors, (d,\ell)-list-disjunct matrices,
MUT_k(r)-families, FUT(k, a)-families, etc.) they match the best known bounds
in terms of size of the structures (the relevant parameter in the
applications). For appropriate values of parameters, our results also provide
the first efficient deterministic algorithms for the construction of such
structures
Brane fluctuation and the electroweak chiral Lagrangian
We use the external field method to study the electroweak chiral Lagrangian
of the extra dimension model with brane fluctuation. Under the assumption that
the contact terms between the matters of the standard model and KK excitations
are heavily suppressed, we use the standard procedure to integrate out the
quantum fields of KK excitations and the equation of motion to eliminate the
classic fields of KK excitations. At one-loop level, we find that up to the
order , due to the momentum conservation of the fifth dimension and the
gauge symmetry of the zero modes, there is no constraint on the size of extra
dimension. This result is consistent with the decoupling theorem. However,
meaningful constraints can come from those operators in , which can
contribute considerably to some anomalous vector couplings and can be
accessible in the LC and LHC.Comment: Revised version, 20 pages in ReVTeX, to appear in PR
The added value of molecular-based diagnostics in the African forensic medical setting
Sudden unexpected infant death (SUDI) is reported to be
an extraordinarily high burden in sub-Saharan Africa, with
the incidence rate in South Africa among the highest in the
world. It is common for the cause of many such infant deaths
to remain unexplained even after a full medico-legal death
investigation, and then to be categorised as a sudden unexplained
infant death (SUID). Fortunately, advances in molecular-
based diagnostics allow researchers to identify numerous
underlying inherited cardiac arrhythmogenic disorders in
many SUDI cases, with a predominance of variants identified
in the SCN5A gene. Such cardiac arrhythmogenic-related
sudden deaths generally present with no structural alterations
of the heart that are macroscopically identifiable at autopsy,
therefore highlighting the importance of post mortem genetic
testing. We report on a significant genetic finding that was
made on a SUDI case in which the cause was ascribed to an
acute bacterial pneumonia but it was still subjected to post
mortem genetic testing of the SCN5A gene. The literature
shows that many SUDI cases diagnosed with inherited cardiac
arrhythmogenic disorders have demonstrated a viral prodrome
within days of their death. It is therefore not uncommon for
these cardiac disorders in infants to be mistaken for flu, viral
upper respiratory tract infection or pneumonia, and without
the incorporation of post mortem genetic testing, any other
contributory causes of these deaths are often disregarded.
This study highlights the need for research reporting on the genetics of inherited cardiac disorders in Africa.The Genomic Research Institute from the University of Pretoria, South Africa.http://www.cvja.co.zaam2023Forensic Medicin
The trade-off between tidal-turbine array yield and impact on flow: A multi-objective optimisation problem
Abstract This paper introduces a new approach for investigating trade-offs between different societal objectives in the design of tidal-turbine arrays. This method is demonstrated through the trade-off between the yield of an array, and the extent to which that array alters the flow. This is posed as a multi-objective optimisation problem, and the problem is investigated using the array layout optimisation tool OpenTidalFarm. Motivated by environmental concerns, OpenTidalFarm is adapted to not only maximise array yield but also to minimise the effect of the array upon the hydrodynamics of the region, specifically the flow velocity. A linear scalarisation of the multi-objective optimisation problem is solved for a series of different weightings of the two conflicting objectives. Two idealised test scenarios are evaluated and in each case a set of Pareto solutions is found. These arrays are assessed for the power they generate and the severity of change they cause in the flow velocity. These analyses allow for the identification of trade-offs between these two objectives, while the methods proposed can similarly be applied to the two key societal objectives of energy production and conservation, thus providing information that could be valuable to stakeholders and policymakers when making decisions on array design
Ensiling quality of maize as influenced by the addition of wet distillers grains with soluble
Wet distillers grains with soluble (WDGS) were blended with whole maize plants on an as-fed basis at 0%, 20%, 30%, and 40% and ensiled in 3 L bottles to evaluate the silage fermentation characteristics and ensiling quality in a complete randomized design. Each treatment was ensiled in 15 mini-silos and three bottles were opened on days 7, 21, 42 and 120. Each treatment was sampled for chemical composition and silage fermentation parameters. There was a steady decrease in dry matter (DM) concentration of silage with increasing WDGS inclusion level over time. Initial pH (at day 0) decreased with increasing level of WDGS inclusion, with 40% WDGS inclusion recording the lowest pH (3.6) at day 120. Lactic acid concentration was slightly lower for WDGS-blended silages compared with the control. In contrast, the acetic acid concentration for WDGS-blended silage increased across all treatments, suggesting a possible diminished effect of clostridium bacteria in the silage owing to a reduced pH. The acid detergent fibre (ADF), neutral detergent fibre (NDF) and IVDOM (in vitro digestible organic matter) did not differ at the time of ensiling among treatments. During post ensiling, ADF increased slightly over time for WDGS-blended treatments (at 120 days). The results from this study indicated that WDGS could be ensiled effectively with maize plants without compromising silage quality.WAVNhttp://www.sasas.co.zaam2016Animal and Wildlife Science
BESII Detector Simulation
A Monte Carlo program based on Geant3 has been developed for BESII detector
simulation. The organization of the program is outlined, and the digitization
procedure for simulating the response of various sub-detectors is described.
Comparisons with data show that the performance of the program is generally
satisfactory.Comment: 17 pages, 14 figures, uses elsart.cls, to be submitted to NIM
- …