3,180 research outputs found
#Feesmustfall and beyond: Towards a sustainable national student loan regulatory framework
Universities have been forced to raise higher education fees with above inflation rates due to increasing operating costs and higher student numbers and decreasing real term government funding. While free higher education or other alternative funding models are being considered, the higher education sector is at stake: a sector that plays a vital role in creating improved lives for all South Africans. A sustainable framework is desperately required or universities will once again need to increase student fees at unreasonable rates to maintain quality. We therefore performed a mixed method documentary analysis to prove that fee-free higher education is not viable in South Africa as significant funds will either need to be reallocated from other sectors that also require funding, or it will have to be collected from already overburdened tax payers. The present study also developed a viable student fee regulatory framework with the use of grounded theory: subsidised higher education with the effective use of the already implemented National Student Financial Aid Scheme
Postmortem tissue distribution of morphine and its metabolites in a series of heroin related deaths
The abuse of heroin (diamorphine) and heroin deaths are growing around the world. The interpretation of the toxicological results from suspected heroin deaths is notoriously difficult especially in cases where there may be limited samples. In order to help forensic practitioners with heroin interpretation we determined the concentration of morphine (M), morphine‐3‐glucuronide (M3G) and morphine‐6‐glucuronide (M6G) in blood (femoral and cardiac), brain (thalamus), liver (deep right lobe), bone marrow (sternum), skeletal muscle (psoas) and vitreous humor in 44 heroin related deaths. The presence of 6‐monoacetylmorphine (6‐MAM) in any of the postmortem samples was used as confirmation of heroin use. Quantitation was carried out using a validated LC‐MS/MS method with solid phase extraction. We also determined the presence of papaverine, noscapine and codeine in the samples, substances often found in illicit heroin and that may help determine illicit heroin use. The results of this study show that vitreous is the best sample to detect 6‐MAM (100% of cases), and thus heroin use. The results of the M, M3G and M6G quantitation in this study allow a degree of interpretation when samples are limited. However in some cases it may not be possible to determine heroin/morphine use as in 4 cases in muscle (3 cases in bone marrow) no morphine, morphine‐3‐glucuronide or morphine‐6‐glucuronide was detected, even though they were detected in other case samples. As always postmortem cases of suspected morphine/heroin intoxication should be interpreted with care and with as much case knowledge as possible
A Property Law Reader: Cases, Questions, and Commentary, 5th ed., Preface and Table of Contents
Nobody has been more influential over the past generation in the teaching of property law in Canada than Bruce Ziff. His Principles of Property Law is the foundational textbook on the subject. A Property Law Reader: Cases, Questions, and Commentary, which he first published as a sole author in 2004, has become, over three subsequent editions, the most widely used teaching material for property law in the country. Bruce retired from teaching property law in 2019. His retirement left major holes not only at the University of Alberta, where he taught for decades, but also throughout Canada in terms of guiding students, mentoring professors, and developing teaching materials and other resources for property law.
Bruce had brought in Jeremy de Beer, Douglas Harris, and Margaret McCallum to collaborate with him on the 2nd, 3rd, and 4th editions of A Property Law Reader, but with his retirement, and also with Margaret’s, after years at the University of New Brunswick, the 5th edition is the product of a new scholarly collaboration with Tenille Brown and Patricia Farnese joining Jeremy and Doug. Although Bruce has stepped aside entirely from this 5th edition, his intellectual contributions remain profound. Much of the material within chapters has been updated or replaced, but the 5th edition retains the structure and organization that Bruce initially conceived. It also retains many of Margaret’s contributions to the selection of material and the commentary.
The preface of the 4th edition began with this statement: “Property law—that body of rules which describes and defines relationships between people with respect to things—involves many choices.” The opening paragraphs continued by emphasizing that these choices, explicit or implicit, involve important decisions about the allocation of resources, and further, that we needed to interrogate the justifications for these decisions. The materials in the 4th edition, and in this 5th edition, return repeatedly to the justifications for particular rules and to ask whether they remain convincing. Indeed, the collection of materials was designed to enable an investigation of property law rules, and of the justifications for them
Planktonic Aggregates as Hotspots for Heterotrophic Diazotrophy: The Plot Thickens
Biological dinitrogen (N-2) fixation is performed solely by specialized bacteria and archaea termed diazotrophs, introducing new reactive nitrogen into aquatic environments. Conventionally, phototrophic cyanobacteria are considered the major diazotrophs in aquatic environments. However, accumulating evidence indicates that diverse non-cyanobacterial diazotrophs (NCDs) inhabit a wide range of aquatic ecosystems, including temperate and polar latitudes, coastal environments and the deep ocean. NCDs are thus suspected to impact global nitrogen cycling decisively, yet their ecological and quantitative importance remain unknown. Here we review recent molecular and biogeochemical evidence demonstrating that pelagic NCDs inhabit and thrive especially on aggregates in diverse aquatic ecosystems. Aggregates are characterized by reduced-oxygen microzones, high C:N ratio (above Redfield) and high availability of labile carbon as compared to the ambient water. We argue that planktonic aggregates are important loci for energetically-expensive N-2 fixation by NCDs and propose a conceptual framework for aggregate-associated N-2 fixation. Future studies on aggregate-associated diazotrophy, using novel methodological approaches, are encouraged to address the ecological relevance of NCDs for nitrogen cycling in aquatic environments
Measurement of neutron capture on Ca at thermal and thermonuclear energies
At the Karlsruhe pulsed 3.75\,MV Van de Graaff accelerator the thermonuclear
Ca(n,)Ca(8.72\,min) cross section was measured by the
fast cyclic activation technique via the 3084.5\,keV -ray line of the
Ca-decay. Samples of CaCO enriched in Ca by 77.87\,\% were
irradiated between two gold foils which served as capture standards. The
capture cross-section was measured at the neutron energies 25, 151, 176, and
218\,keV, respectively. Additionally, the thermal capture cross-section was
measured at the reactor BR1 in Mol, Belgium, via the prompt and decay
-ray lines using the same target material. The
Ca(n,)Ca cross-section in the thermonuclear and thermal
energy range has been calculated using the direct-capture model combined with
folding potentials. The potential strengths are adjusted to the scattering
length and the binding energies of the final states in Ca. The small
coherent elastic cross section of Ca+n is explained through the nuclear
Ramsauer effect. Spectroscopic factors of Ca have been extracted from
the thermal capture cross-section with better accuracy than from a recent (d,p)
experiment. Within the uncertainties both results are in agreement. The
non-resonant thermal and thermonuclear experimental data for this reaction can
be reproduced using the direct-capture model. A possible interference with a
resonant contribution is discussed. The neutron spectroscopic factors of
Ca determined from shell-model calculations are compared with the values
extracted from the experimental cross sections for Ca(d,p)Ca and
Ca(n,)Ca.Comment: 15 pages (uses Revtex), 7 postscript figures (uses psfig), accepted
for publication in PRC, uuencoded tex-files and postscript-files also
available at ftp://is1.kph.tuwien.ac.at/pub/ohu/Ca.u
Dependence of direct neutron capture on nuclear-structure models
The prediction of cross sections for nuclei far off stability is crucial in
the field of nuclear astrophysics. We calculate direct neutron capture on the
even-even isotopes Sn and Pb with energy levels,
masses, and nuclear density distributions taken from different
nuclear-structure models. The utilized structure models are a
Hartree-Fock-Bogoliubov model, a relativistic mean field theory, and a
macroscopic-microscopic model based on the finite-range droplet model and a
folded-Yukawa single-particle potential. Due to the differences in the
resulting neutron separation and level energies, the investigated models yield
capture cross sections sometimes differing by orders of magnitude. This may
also lead to differences in the predicted astrophysical r-process paths.
Astrophysical implications are discussed.Comment: 25 pages including 12 figures, RevTeX, to appear in Phys. Rev.
Controlled Crystallization of the Lipophilic Drug Fenofibrate During Freeze-Drying: Elucidation of the Mechanism by In-Line Raman Spectroscopy
We developed a novel process, “controlled crystallization during freeze-drying” to produce drug nanocrystals of poorly water-soluble drugs. This process involves freeze-drying at a relatively high temperature of a drug and a matrix material from a mixture of tertiary butyl alcohol and water, resulting in drug nanocrystals incorporated in a matrix. The aim of this study was to elucidate the mechanisms that determine the size of the drug crystals. Fenofibrate was used as a model lipophilic drug. To monitor the crystallization during freeze-drying, a Raman probe was placed just above the sample in the freeze-dryer. These in-line Raman spectroscopy measurements clearly revealed when the different components crystallized during freeze-drying. The solvents crystallized only during the freezing step, while the solutes only crystallized after the temperature was increased, but before drying started. Although the solutes crystallized only after the freezing step, both the freezing rate and the shelf temperature were critical parameters that determined the final crystal size. At a higher freezing rate, smaller interstitial spaces containing the freeze-concentrated fraction were formed, resulting in smaller drug crystals (based on dissolution data). On the other hand, when the solutes crystallized at a lower shelf temperature, the degree of supersaturation is higher, resulting in a higher nucleation rate and consequently more and therefore smaller crystals. In conclusion, for the model drug fenofibrate, a high freezing rate and a relatively low crystallization temperature resulted in the smallest crystals and therefore the highest dissolution rate
The s Process: Nuclear Physics, Stellar Models, Observations
Nucleosynthesis in the s process takes place in the He burning layers of low
mass AGB stars and during the He and C burning phases of massive stars. The s
process contributes about half of the element abundances between Cu and Bi in
solar system material. Depending on stellar mass and metallicity the resulting
s-abundance patterns exhibit characteristic features, which provide
comprehensive information for our understanding of the stellar life cycle and
for the chemical evolution of galaxies. The rapidly growing body of detailed
abundance observations, in particular for AGB and post-AGB stars, for objects
in binary systems, and for the very faint metal-poor population represents
exciting challenges and constraints for stellar model calculations. Based on
updated and improved nuclear physics data for the s-process reaction network,
current models are aiming at ab initio solution for the stellar physics related
to convection and mixing processes. Progress in the intimately related areas of
observations, nuclear and atomic physics, and stellar modeling is reviewed and
the corresponding interplay is illustrated by the general abundance patterns of
the elements beyond iron and by the effect of sensitive branching points along
the s-process path. The strong variations of the s-process efficiency with
metallicity bear also interesting consequences for Galactic chemical evolution.Comment: 53 pages, 20 figures, 3 tables; Reviews of Modern Physics, accepte
The reliability of the patellotrochlear index on magnetic resonance imaging for measuring patellofemoral height
Background: The purpose of this study was to determine the inter-and intra-observer reliability of the patellotrochlear index (PTI) on magnetic resonance images (MRI) in patients with patellofemoral pain. The correlation between the PTI measured on MRI and the modified Insall-Salvati (MIS) ratio measured on radiographs was also assessed. Methods: The PTI was assessed on MRI images and the MIS ratio on radiographs of 66 knees of 62 patients. Assessment was performed by two orthopaedic surgeons, one orthopaedic surgery registrar, two radiologists and one radiology registrar. Correlation coefficients, standard errors of measurement and limits of agreement were calculated for the PTI. To assess the association between the PTI and the MIS ratio, the Pearson's correlation coefficient was calculated. Results: The PTI showed good interobserver reliability (intraclass correlation coefficient (ICC) 0.79; 95% confidence interval (CI) 0.73-0.85) and excellent intra-observer reliability (ICC 0.90; 95% CI 0.89-0.91). The standard error of measurement was 0.05 and limits of agreement with the mean +/- 0.09. A very weak and not significant correlation was found between the PTI and the MIS (r = 0.02; P = 0.77). Conclusions: The PTI showed good interobserver reliability and excellent intra-observer reliability. In order to conclude which measurement method of assessing patellar height is truly the most reliable, future studies should investigate agreement parameters (standard error of measurement, limits of agreement) besides solely correlation coefficients. We found a very weak correlation between the PTI and the MIS which suggests that at least one index has poor validity. Future validity studies on indices to assess patellar height are necessary. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
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